PART TWO

When he at last convinced himself that he had got through the Atomic

Curtain, O'Hara said, his first feeling was a wild and utterly

unreasoning elation.

"I've done it!" he kept repeating to himself, much as if he had booted

home a twenty-to-one shot at the races at Aintree. "I've actually done

it--the first man in two hundred and seventy years to smash through.

Now we shall see!"

But that exuberance did not long continue. For here he was, presumably

in the Western Hemisphere, the cradle of the future, a terra incognita

since that Third World War, and it seemed no different from the polar

regions that he had been flying for the International Patrol. No

different at all--the limitless gray reaches of the sky, the same vast

twisted sheets of polar ice pierced only at great intervals by craggy,

barren peaks--the islands of the Beaufort Sea, above the northern coast

of Canada.

O'Hara was cruising at two thousand miles an hour. His fuel gauges

indicated that he might keep going for three thousand miles, depending

on his altitude. It was necessary, he knew, to get above forty

thousand feet and to stay there for his best distance, and he had

to have distance toward the south--for the storms of December would

have driven snow deep along the lost continent of North America. He

was not equipped for any lengthy existence in snow. His craft had the

Patrol's usual paraphernalia--an inflatable boat, a signal pistol,

a .38 automatic with six clips of ammunition, emergency water supply,

emergency rations, the items considered indispensable when a rescue

team could be expected to begin search soon after he failed to report

to his base at Wrangell Island. But now, south of the Curtain, no

rescue team was coming. None could get through. In consequence, his

life depended on getting below the wasteland of the Arctic.

These things, O'Hara said, ticked automatically through his mind in

those first few minutes after he realized that he had got through the

Curtain--these, and the overwhelming importance of the fact itself,

that the Curtain could be pierced. He had, of course, no idea how the

thing had been achieved. It had happened while he was unconscious, but

as he reasoned it, his craft must have spun from north to south and

then rammed through. Nor had he any data on the milliroentgen count of

the Curtain itself--he had no idea of the contamination to which he

had been exposed. He realized that at this moment he should have been

a charred mass of carbon, like the bodies of those men on Coronation

Island, in the Antarctic, after their vessel of logs had drifted into

the Curtain.

But the indisputable fact remained that he was not carbonized. He could

only accept it and take whatever precautions seemed most likely to keep

him alive, which now, at this moment, seemed to call for flying south.

Within minutes he was crossing a coastline, and following the bed of

a frozen river that pointed roughly south. Far toward his right--the

west--the saw-toothed stubs of mountains poked their glittering

ice-sheathed peaks up from the continent, and O'Hara was remembering

the maps he'd studied as a boy. That way, the west, must be Alaska.

Again he checked his position in latitude and longitude, then deciding

that the river course below him must be the Mackenzie, reaching down

past Great Bear Lake in Canada toward Great Slave Lake. And somewhere

distant past the snow-packed tundras toward the east would be the

land-locked gulf of Hudson Bay.

"Remember," O'Hara said, "I wrote that time telescopes in the Patrol?

It was telescoping for me now--I was back again with old Hendrik

Hudson, though thank God not in quite the same kind of boat. I was

opening up the West again, seeing the amazing continent, the wonders

that I'd seen before only as dotted lines and red-and-blue ink sworls

on long-forgotten maps. And in five minutes--the five since I had

passed the Curtain--I was exploring more of this tremendous northland

than old Hendrik ever dreamed of."

Wonders, yes--but wonders unfortunately very like those of the land

mass of Siberia, and so no different from what he'd known before he

smashed through the Curtain. O'Hara felt somehow as if the myths of the

Lost Continent had let him down. Until he noticed the recording of his

scintillometer.

It had dropped only to .305 milliroentgens an hour. That was

high--dangerously high according to the flying regulations of the

Patrol, yet it had been much higher further north, toward the Curtain.

He could only hope that with his progress south the count would

gradually decline. Then it occurred to him that radioactive water might

be running underneath the ice of the Mackenzie, draining southward

from the Curtain, and he swerved hard toward the east, leaving the

river bed some hundred miles behind before he made another reading.

The milliroentgen count, rather than dropping, had risen to .325

an hour. And simultaneously O'Hara's memory dredged up a curious

fact--the Mackenzie flowed toward the north. It could not possibly be

contaminated from the Curtain.

O'Hara now turned again toward the west, crossing the Mackenzie and

heading for a tremendous region of ice-capped peaks, their vast flanks

swathed with the silver sheen of the greatest glaciers he had ever

seen--the northern reaches of the Rockies, he concluded, the neckbones

of the spinal column of the continent.

In this race westward, his milliroentgen count was sliding steadily,

until, above the mountain chain itself, the count seemed stabilized at

last at .285. Yet when he pushed beyond, toward the western coast--the

Pacific--the count immediately began to jump again. He made the

indicated correction in his flight, adhering to the southeast curvature

of the mountain chain, and concluding that he had discovered a corridor

of lesser contamination, its base upon the Curtain in the north, and

its two flanks, on the eastern and western sides of the mountains,

strongly radioactive.

He had now been below the Curtain--below, that is, the northern ellipse

of the Curtain, for it was known to enclose the Atlantic and Pacific

coasts as well--for thirty minutes, boring steadily south despite the

zigzag pattern of his exploration, and the character of the terrain was

changing, not less mountainous but with some indications of a seasonal

variation in the snow pack, for oftener now the bare rock precipices

and peaks showed through, and beyond the upraised spine of the Rockies,

toward the distant shimmering deep blue of the Pacific, the snow itself

had taken on a stippled appearance--immense forests, O'Hara concluded,

blanketed but shaping the white countours upon them. And farther still,

merging into the rim of the ocean's curve, lay a varying band of dark

brown and black and vivid green, presumably a thickly forested shore,

completely free of snow. O'Hara made a quick calculation based on his

known altitude and an approximation of the distance to the horizon.

The result astonished him. The forest belt extended inland for three

hundred miles.

Yet the flight was becoming monotonous to the point of lulling him.

The letdown that followed his discovery that the upper reaches of the

continent were so remarkably similar to Siberia had increased, and with

the passage of time he felt his eyelids inexorably closing. There was

nothing to it. The dreaded continent was a fable made mysterious only

by distorted memories of its history. It was, after all, a hoax--an

empty shell, and he was penetrating deep--

His next thought jerked him erect in the cockpit of his craft. Suppose

it was in fact an empty shell? Suppose there was nothing in this

immensity behind the Curtain, the land which had been his fathers'

fathers, but these ice-choked rivers and frozen tundras and forests

and these tortured and interlocking mountain chains? Suppose it was

dead--without life?

And it well might be. O'Hara himself had been exposed steadily now

for the better part of an hour to a degree of contamination that the

International Patrol considered beyond dangerous, and in his flights

to the east and west he had plunged through belts exceeding .300

milliroentgens an hour. Was it not probably that these Americans in

establishing their Atomic Curtain had simultaneously contaminated their

two continents beyond endurance? The suicide of a race?

In an instant of panic, O'Hara swung in a tight arc to the north. He

had, he felt, only the one chance to escape--a dash at maximum speed

back to the Curtain and through it.

But, as instantly, he discarded that. Whatever it was that had got

him through the Curtain in the first place could not be expected to

work twice. He was convinced that it had been a kind of providential

accident, something to do with that splitting blast of electrical

power in the thunderhead, and he was here, within this Western

Hemisphere, inescapably cut off.

His reason, too, came quickly to his rescue. These mountains and the

far slope toward the Pacific Coast were smothered in their forests. And

trees were life--biological life. If there was plant life there would

be germination, bacteria--surely animal bacteria, surely animal life at

however low a scale. Though perhaps not men.

Perhaps not men! Then this was indeed the grand adventure. He headed

south again.

All these speculations and the resultant skittering about, as O'Hara

said, had eaten into his flying time and he had not made the progress

that he had anticipated, yet it was not quite two o'clock, not ninety

minutes after he had crashed through the Curtain, when O'Hara saw a

compelling flash of light upon his right. It was the first time that

he had been conscious of the increasing clarity of the sun, no longer

so obscured by clouds or ice fogs. O'Hara spiraled down toward a wide

plateau, ringed with a lesser inner range of mountains.

The flash, he discovered, was reflected from a rectangular object,

rather like a huge jewel, set into the face of a tall pile of masonry

that reached some thirty stories high, a single needle rising from the

snow-clad plain. Losing altitude fast, very nearly making of it a power

dive, O'Hara pulled out of it level with the tower--for that was what

it proved to be, a giant tower of stone and metal, expertly fashioned,

a glittering and soaring pinnacle unlike anything that he had ever seen.

The flash was a reflection from the gemlike surface, which apparently

was glass. The upper story seemed to be a kind of solarium, with six

facets so arranged that they caught the sun constantly. The stories

below it lacked openings of any sort, and O'Hara concluded that if in

fact the tower had once been used for offices or dwellings those who

lived there had relied entirely upon indirect lighting.

He was convinced that it was deserted now. There was a complete

deadness to it, a stone and metal tower rising abruptly from a

snow-blanketed plain, long abandoned, long forgotten. And descending

lower, he could make out the geometric patterns of low structures and

broad avenues, but with a skeletal emptiness about them, the roofs

collapsed, the walls themselves in many places having toppled into the

general ruin. A dead city, certainly, yet once it must have been a

metropolis, culminating in its strange, massive tower before it died.

"Forgotten names from forgotten histories came back to me," he said.

"The northwest coast--not Vancouver? Not Seattle? No, for both of them

had been upon the coast itself. Spokane, then? Or possibly some city

that had flourished after the establishment of the Curtain? But it

did not matter, the place was dead, with the anonymity of the dead. A

graveyard of a civilization that had been the mightiest on earth. Yet

the proof that this civilization actually had existed--that it was no

myth--was enormously stimulating to me. It was my second big moment."

The tower and the ruined city had taken his attention from the

business of flying. Now suddenly he was startled by the rapid-fire

of his scintillometer. It was recording .400 milliroentgens an

hour--unendurable!

"The dead," said O'Hara, "were reaching out for me. They wanted me,

an alien probing through the skies above their tomb. And I felt

their hostility, as if a shower of warheads had come roaring up. The

contamination was as murderous as any warheads would have been."

The tautness of his steep climb skyward and sharp swerve back toward

the spinal cord of the continent precluded any further observations.

He was now acutely alarmed. He expected at any moment to discover upon

his body the raw violence of radioactive burns, he anticipated bleeding

and there was at the hinges of his jaws a definite sensation of nausea.

Yet moments passed without development of these symptoms. The nausea

abated. He was not stricken yet, or if he was, the effects were not

yet obvious. And this raised possibilities of conditioning to the

contamination that had never been explored--that no one, in the world

he knew, had dared to explore. It might yet prove to be that man could

exist in these extremes of radioactivity.

Large mottled patches now were appearing between the pale blue-white

stretches of endless snow. The mountain peaks and the high plateaus

still presented their heavily drifted appearance, but in the deeper

valleys an occasional ice-free river twisted, seeking its outlet either

toward the east or west--the east, O'Hara remembered, would lead

to the intricate arterial system that would at last merge into the

Mississippi River, the continental sewer that dumped its burden of silt

and debris into the swampland delta of--what was it? Louisiana? The

whole once-familiar pattern of maps he had intensely studied as a child

now was coming back vividly--the two mountain systems, Appalachian and

Rockies, the great valley of the Mississippi, the Atlantic and Pacific

coastlands, the spider web of fabulous cities, names like New York and

Washington, Chicago and Kansas City, Los Angeles and San Francisco,

and somewhere in these Rockies which he was now following were--or had

been--Salt Lake City and Denver.

There was a definite excitement in these names that for O'Hara rolled

back the drab present to that glittering past, when the word _tomorrow_

had meant more than a repetition of today.

O'Hara felt positive now that he had established a second major fact.

For almost two hours he had been flying these forbidden skies, yet

no patrol--save the atomic radiation of the dead city--had so far

challenged him. It was inconceivable that any important civilization

could exist upon the northernmost of the two Lost Continents without

patrolling its skies, and consequently, if a civilization did exist,

it must have shifted to the south, leaving these wastes. But for some

minutes past, he had observed a peculiar series of geometric designs,

resembling the drawings of ancient Cretan labyrinths, far below him on

the frozen surface. He now was approaching another of these, extending

for miles upon the floor of a wide valley, and very cautiously, with

his eyes constantly flicking back to his scintillometer, he began to

descend toward it, diving.

As rapidly, his milliroentgen count began to climb, reaching .290

within the first five thousand feet of descent, then to .300 when his

altitude was down to 30,000 and jumping very sharply at 24,000 feet

to .325. The strange labyrinth was much too hot for inspection. But

the regularity of its form seemed proof that it was man-made, and that

decided O'Hara. He continued down until his altimeter registered 5,000

feet.

The labyrinth's pattern was precise. It was composed of an almost

infinite number of thick parallel lines, joined at the ends, so that

it actually resembled an endless pipe, though various segments of it

were colored in a multiplicity of pastel shades--a vast farm of pipes,

reaching for miles across the valley's floor, its purpose not apparent

to O'Hara. His milliroentgen count now was approaching .400, and again

he made that steep climb back to 40,000 feet.

These pipe farms soon were visible in every major valley, and further

toward the east, upon the great slope of the plains toward the

Mississippi, they were everywhere like the squares of a continental

checkerboard, in some places partly obscured by snow drifts and in

others lying exposed to the sun's brilliance.

For 130 minutes of continuous flying through this long corridor south

of the Atomic Curtain the milliroentgen count had remained almost

steady at .295, but at 2:30 P.M., and without an obvious physical

reason for it, the count suddenly made an abrupt rise even at the

40,000-foot level at which he was flying. O'Hara tried swerving both

to the east and west, also changing altitudes, but the contamination

continued rising above .400 with every second's flying time. Here was a

new phenomenon--a density of radiation that indicated some intense new

barrier, and moments later O'Hara saw a strange, enormous white oblong

reaching from east to west, not quite to the horizons but effectively

spanning the area that he had determined composed the north-south

corridor of least contamination. And such was the milliroentgen

count that O'Hara felt it must in some way be a source--or excessive

consumer--of atomic power. O'Hara's latitude calculation fixed his

position as the southern part of the state of Colorado. The long

corridor was in truth a closed rectangle, a box--a coffin without

escape. He could only turn north again into it.

But the arc of his explorations had swung him well toward the east,

and in these seconds he passed once more above the ruined debris of an

empty city, the same pattern of collapsed roofs and time-desiccated

walls extending for miles around a single sky-piercing tower of

stone and metal with that glass-encased solarium at its summit. And

this time, although it was gone in an instant, a place name fixed

itself in O'Hara's mind, corroborated by his memory of latitude and

longitude--the sky-high city of Denver.

His milliroentgen count was dropping back toward the .285 level he had

anticipated, but all at once his motors cut out on him. His fuel was

exhausted.

"There are such things as heroes," said O'Hara, and paused, tilting

back in the comfortable easy chair of his Bloomsbury flat, a fresh

drink in his hand. He took a long pull at the glass, reflectively.

And for a moment it was as if we were stepping back across the Atomic

Curtain, both of us, back from the Lost Continent, taking within a

second's time a giant stride from unreality into the stodginess of

present-day London. O'Hara smiled crookedly. "Yes," he continued,

"there are such things as heroes--Tournant is rather close to it, I

think. He has the courage to do what he can do, and to reject what

he cannot. That's a hero in my book. But I'm not and never was, and

when I heard the last unhappy cough from my motors and realized quite

definitely that I was in for it, my knees were wax. No, not that

crusty--they were jelly. When I understood that I was going down and

that my craft, which until then had given me some sense of decision,

was nothing now, dead metal under me--well, fear does crazy things to

you. I screamed. It's true, I bellowed like a gored ox, striking both

fists at my altimeter, shattering it. Until at last the needle, broken,

jammed."

After that, he said, he was much too busy for theatricals. The peaks

were coming up toward the belly of the plane like sharks' snouts in an

open sea. He stalled to cut his landing speed, and at the last second

pancaked on a meadow free of trees, cushioned by deep snow.

His craft was not damaged. With fuel, and without the waist-deep

snow, he could have taken off again. These were the things a flyer

automatically would check, the normal things. He was out of the

craft, checking the terrain, when the third thing came to him and he

stood there, cursing in the four languages that he knew best. He had

forgotten his wireless. As instantly as he had gotten through the

Curtain, whether help was or was not possible, he should have messaged

his Wrangell base, for the only factor of this personal disaster that

had actual significance was that the Curtain could be pierced--not

once in ten thousand times, perhaps, but it could be done. And that

information should have been relayed at once to Wrangell.

For the next half hour O'Hara worked furiously for contact, with only

the nasty mocking whine of space coming back to him. He had flown too

far. They could not hear him.

"It closed my record in the logs of the Patrol. Like Anstruther, I'd

vanished, leaving nothing but hysterical last words, as valueless to

science and my people as the twitterings of starlings on a summer

evening."

Night deepened his gloom. He shut himself inside his craft, placing

his automatic on the seat beside him, a loneliness that was like coma

sapping him.

"Old Hendrik Hudson--drifting in an open boat among the floes. I think

I really understood at last. For time had ceased to telescope for me.

Time, too, had frozen. As it must in death."

But once, awakened in the night by a sudden howling that was shriller

than the wind would be, he gripped his automatic, peering out, watching

a ball of fire not far above the surface of the ground that vanished

suddenly, as if puffed out. It did not come again. Or if it did, he was

asleep, his will a victim of exhaustion and despondency.

When he awoke, the sun was high above the surrounding peaks. O'Hara

broke out his emergency rations, afterward climbing from the craft to

scoop up and swallow a handful of snow.

"What am I waiting for?" he wondered.

Yet he hated to leave the craft. It was his fortress, both physical and

mental, his one link with the world beyond the Atomic Curtain--though

a useless link now, he knew. It was futile to stay with it and, so far

as he could foresee, futile to leave it. At last the very pressure of

idleness drove him to action and he took his automatic, loaded it and

strapped it beneath his flyer's jacket, then with his ice ax chopped

down a score of small conifers and arranged them around and above his

craft in a crude camouflage. He turned toward the forest that encircled

the meadow and began trudging through the snow. But just beyond the

first line of trees he stopped.

The snow there was trampled as if through the night a Rugby team had

had a go of it, and lying there, used up, blackened with smudge, was a

flambeau of sorts--a length of wood with charred brush lashed to it.

O'Hara ran his finger through the soot. It left a smear of oil.

Petroleum! Life for the motors of his craft. And somewhere near--his

search had purpose now.

"I don't know what the devil I really thought I'd do with fuel,"

said O'Hara. "Fly around in that infernal corridor, I suppose, like

a bullfinch in an aviary, free as all getout until I wanted to go

somewhere beyond it. The truth is, all that seemed to matter was the

chance of taking off again. That's what the Patrol does to you--puts

pinfeathers on your brains. I wanted that fuel. And bad."

The trail led backward through the forest, a series of lines converging

as if the individuals of a herd had searched in scattered formation

toward this one meadow on the top of this one mountain, yet a

preponderance of feet had trampled south by east, and O'Hara followed

that line, keeping his jacket open for quick access to his automatic

and using his ice ax when he needed it to chop through underbrush.

"You've seen a gull walk, haven't you? He's out of his natural element

and he waddles--fine enough flying, and very good in the water, but

he walks--well, like a gull. That was how I felt on foot, scrabbling

through that forest," said O'Hara. "Most of it was downhill work, which

helped, and presently the brush thinned out and the trees got larger

and fewer and I was doing a passing fair job of it, following that

trail until it was well after noonday, when I leaned against a ledge of

granite for a breath."

But he did not quite get it.

"I gulped at it--and then I gave it up entirely. For crouching on the

ledge above was an enormous cat. When I say enormous, don't imagine

a lion. The king of beasts is a stinking coward, but this creature

stalking me was making a little game of it, a kind of homicidal

little game--its eyes pale yellow with insanity and its two fangs a

greenish yellow and larger than the tusks of a walrus. Had it leaped,

I would not have known it, not for more than the instant it takes a

severed jugular to spurt your life's blood out. As I say, I did not

get that breath--I fired, quite sillily without aiming, but the bullet

splattered through one of those yellow eyes into its brain."

And while it threshed, O'Hara walked less like a gull. But he was not

altogether getting away from the creature. The sight of those tusklike

fangs kept coming back to him, insistently, hammering away at some

obscure little wrinkle of his memory, until at last the two words

formed and were upon his lips, "Saber-tooth!"

It was absurd. It could not possibly be that. And yet it was--the

cat had been a saber-tooth, or surely like the skeletons of those

long-vanished, blood-imbibing killers of the North American continent.

O'Hara could not bring himself to put his automatic inside his jacket

after that. He stuck to the trail of trampled snow, following it down

the slopes of the mountain. Gradually the tracks seemed fresher, the

snow less melted after it had been disturbed. He began to move more

cautiously.

He was passing through a defile, toward an opening in the rock

beyond, when he first realized that he was being watched. How long

this had been going on he could not guess, for the indication was not

conclusive--a shower of loose rock slid down from above. When O'Hara

looked up, he thought he saw a head disappearing into the overhanging

brush. He halted instantly but there was no sound, nor did the head

reappear. After a few seconds he realized the stupidity of remaining

exposed in this narrow passage, a clay pigeon for whatever might be

hiding on the ledges above him, and he began running.

Once more small rocks came cascading down toward him, and this strange

barrage continued, always just behind him, driving him along the trail

of trampled snow through the defile. Whoever had preceded him had

managed to get through, and O'Hara kept at it, breaking finally into

the open--a sort of natural amphitheater. And there the trail ended.

The footprints now diverged toward the walls of sheer rock, on which

there was no snow to preserve them.

"I was trapped," said O'Hara. "They had driven me into it as you might

drive a hare. It was possible, of course, to get out of that bowl--for

they had got out of it!--by climbing up those walls, thirty or more

feet, but for that I'd want an Alpine guide, preferably with the rope

to pull me up. I turned back instantly toward the defile and made a run

for it."

This time, when rock came down, it came in slabs. Nor was he able this

time to detect any movement in the brush above.

"I might have got through," said O'Hara. "They might have missed me.

But they seemed a little too expert and I preferred to wait, well back

from the sides of the bowl, with my automatic ready."

They let him wait until after dusk. Then, very deliberately, a

lighted flambeau was thrust out from behind a boulder high above him,

definitely a test to see what he would do. He stayed where he was and

did nothing.

Other flambeaux now began appearing, neither advancing nor wavering,

but fixing him in the center of their glare for a purpose not

yet obvious. It was a game they played, O'Hara felt, a childish

hanky-panky. But there had been nothing childish in those slabs of rock.

A wild shout from the rocks above now startled him, and through the

defile, with ceremonial lack of haste, a lone adversary was advancing,

armed only with a tapering wooden club and wearing a garment made

of skins that reminded O'Hara of Scottish Highland kilts, the feet

and lower legs thickly encased in furs bound with spiraling rawhide

thongs, a heavy parka covering the head and face--expert work, all of

it. The intruder, although of lesser stature, moved forward with such

confidence that O'Hara's automatic felt ridiculous to him.

"Unsportsmanlike," he said. "You just don't shoot a man whose only

weapon is a piece of carved wood, particularly not when you know that

perhaps a hundred of his crowd are hiding in the rocks above you. I

shoved the automatic inside my jacket. As you know, I used to wrestle,

and while I measured him at possibly one hundred eighty pounds, I

thought I could manage, if they'd keep those slabs off me."

As they turned, facing each other in the dark, O'Hara was conscious

that the number of flambeaux above him had increased and were inching

forward, and very dimly now he could detect the outlines of their

parka-covered heads. The game was approaching a climax.

It came with a rush. His opponent leaped suddenly, swinging the carved

club straight for O'Hara's head, a blow that would have crushed his

skull had it struck home, but he ducked beneath its arc, coming up

under the descending arm. He grabbed it, whirled and threw his heavy

shoulder up, sending his opponent flying through the air.

O'Hara picked up the club. His opponent, recovering quickly, now

scrambled up and charged again, and O'Hara, his mind concerned most

with the throng above, made his second decision--he dropped the club

and stood there waiting. The next instant he was knocked from his

feet by the ferocity of the charge, but in falling he locked his arms

around his opponent's neck, attempting again a variation of the trick

he'd used before, but momentum broke his hold and he fell backward.

Instantly he saw the warclub rising.

The blow crashed into the muscles of his shoulder. He rolled beneath

it, got onto his knees just as a second blow splashed blood into his

eyes, then plunged again. His groping fingers found the club and

wrenched it loose and this time he forgot it was a game--in close, he

struck. His opponent toppled backward and lay still.

"I felt," said O'Hara, "rather like reciting a few lines from Horatio

at the bridge. Or Spartacus. For my head was splitting. But the

flambeaux were moving closer. I could see who carried them now--big

fellows, perching up there in the box seats as if they might start

throwing pennies to me. I waved the club to them. At the moment I think

I would have fought the pack of them, for I was boiling--I'd been

roughed up and I never had liked that. And then something touched my

foot."

His adversary had crawled across the snow and was reaching out, hand

supplicant. The parka had fallen back. It was a woman.

"She held on to my knees and looked up at my face, a mass of waist-long

auburn hair now loose upon her back. And she was beautiful--her hair

reflecting firelight from flambeaux, deeply auburn, her eyes the blue

of glacier ice--a classic face, exquisite, but no tenderness as we know

it. Only passion.

"Quickly she got to her feet, her arms locking me close against her

splendid breasts, an Amazon who worshiped only strength, which I was

glad I had, for those above us now were coming down the sheer walls of

the amphitheater like so many chamois, bringing their flambeaux with

them. Let me repeat--big fellows! Six-six on the average, and running

upward of two-thirty, chests like bulls. And so damned agile! To see

them scamper down that precipice toward me, depending on the quickness

of their feet where I would certainly have found my hands not adequate,

depressed me. I had the warclub and of course my .38, but if they meant

to take me, neither was enough."

Instead, they lined up on both sides of him, then waiting while the

woman motioned him to follow her, and began to lead the way. So at last

they moved off in that strange procession, guided by flambeaux through

the night, much as a bridal couple might move underneath an arch of

swords.

"The simple act of splitting her noggin seemed to have inflamed--be

damned if I'll tell it. Most natural thing in the world, I suppose,

when it's the local custom. Yet it was embarrassing. And the studied

indifference of our escort made it worse. How does one make love on the

march, surrounded by a hundred men? For hours!"

Gradually they were descending the mountain, coming finally beneath

an overhanging cliff into a narrow chasm, and there, around immense

bonfires, a swarm of women and children waited--had waited, O'Hara now

felt certain, throughout the long absence of their men, for all at

once, silent but busier than ants, they began dragging great haunches

of meat from a series of caves which were eroded deep into the stone

face of the cliff, arranging them upon the fires to roast. O'Hara's

woman indicated that they were to sit, and the men now ground out in

the sand their smoking flambeaux and squatted beside them, silent,

impassive, waiting.

Primeval, said O'Hara. There could have been nothing like it

since--what were those ancient caves in France? Cro-Magnon man? The

old boys who drew perfect little sketches of buffalo on the stone

walls of caves? These silent giants, these women with their thick,

abundant hair, the cliff and the caverns, the smell of roasting flesh,

the constant scampering of fur-swaddled babies in the sand--primeval,

certainly. The tribe--the clan!

Someone was chanting. It was the oldest of the men, using words that

were no language that O'Hara knew, yet vaguely familiar. And as others

joined in, the men's voices rich in a monotonous refrain, the women's

working out a hymnlike counterpoint, O'Hara's woman arose and took him

by the hands.

The chant changed now, a lament in it, a grieving for lost things, the

women's voices dominating, keening, almost crystalline in iciness,

like music locked within the chill stone of cathedral towers. O'Hara's

woman led him toward one of the caverns, moving slowly, somberly erect.

Within, deep in the gloom, a log fire smoldered. Smoke made fantastic

shadows leaping on the living rock. She turned at last and stood there

rigid, facing him.

Outside, the chant was changing now, a jubilating chorus of men's

voices, gaining tempo until suddenly they ceased, and from the

breathless silence finally a voice incredibly high, seeming incredibly

remote, sang adoration.

O'Hara's woman freed his hand, then loosening a thong across her

shoulders, shook herself, and stood there in the firelight nude. And

the next instant she leaped at him, her hands like claws, tearing at

his face and throat, driving him backward toward the entrance of the

cave, back toward the clan. It was repetition of the struggle in the

natural amphitheater, savage, passionate, and with O'Hara understanding

now that he must master her or die. He swung his wooden club.

"She fell," he said. "I was getting expert at it--she fell, and that

was it. Brutal, you think? Perhaps. I will not argue that. What

mattered was that Nedra did not think of it that way. That was her

name, Nedra--I learned that, as I was to learn so many things within

the next few days."

But that learning came swiftly only after he understood their language.

It was a decadent English, elided and bastardized and purified of

abstracts, a working language for mountain people, verbs and nouns,

only the simplest adjectives. The trick of understanding it was not to

attempt to get it word for word--the words themselves no longer had

their English identity--but by complete sentences, for three syllables

might express an idea which in the original of his school days would

have required ten or more words. Much of it depended of course on

inflections, whether a question or a command or a statement of fact.

And yet, slurred in his mind's ear, repeated rapidly, it suggested

the more complex English structure, always excepting the abstract. Or

ideas born since the establishment of the Atomic Curtain. It was not

difficult, once O'Hara had grasped the basic sounds.

His key to it, his teacher, was Nedra. For two days and nights, by

custom of the clan, O'Hara was not permitted to leave the nuptial cave,

Nedra herself going only to procure what was necessary in food and

water, returning then at once and always with that mating ferocity of

her people.

"Violence," said O'Hara, "but not the implied violence of our

corrupted European customs, not the ring and the finger, not the

bridal veil--actual violence, the club and the ripping hands, and

finally submission to the master sex, was implicit in their rituals

as it was in their lives constantly. The original combat in that

snow-packed amphitheater actually was our marriage by their custom,

later consecrated in the chants outside the cavern. Neither a ceremony

taken lightly--and not one forgotten readily. Not a blurred memory of

dress uniforms and flowers but as sacred, I think. And vastly more

impressive. As for courtship, as we know it, what is it but a rather

futile attempt at premarital adjustment? Nedra had watched me kill the

saber-tooth, and while I claim no valiance in it she had thought it

admirable. She'd wanted me. I'd proved myself sufficiently before her

people in the amphitheater. It was that simple.

"But with passion and loyalty and respect--which she demanded that I

earn--did not come tenderness. Not then or ever. I had to learn that

lesson. Nedra was not for the meek. And weakness would have sickened

her. It was, I confess, disturbing to learn that I must always be on

guard, that between us there could be no gentleness, that the carved

wooden club, the symbol of marriage, must ever be ready to strike, but

once I had got over my namby-pamby notions, I found myself--well, smug

about it. I too could rule my cave."

Yes, a cave-dwelling people, said O'Hara, but not quite so primitive

as he had supposed. It was on his third day with the clan, after he

and Nedra had at last emerged from the nuptial cavern--O'Hara could

follow the language by now, usually getting it the second or third time

that something was said to him--that he discovered a facet of their

culture that amazed him. He had gone with the gray-haired leader of

the ceremonial chant, called simply the Elder--men's names, he was to

learn, were functional, last names inconsequential--just beyond the

chasm of the caves along a mountain trail with a group of children who

were hauling fallen timber, when from a bank of dense ferns a giant

bear reared up, a bear resembling the Kodiak that O'Hara had known

in Siberia, beyond the Atomic Curtain, but vastly larger, an immense

shaggy beast, awing, the rumble of the thunder in its throat.

The children froze. And before O'Hara could get out the .38 strapped

inside his jacket, the Elder stepped forward, leveled his fist

and fired--the spurt of smoke and flame and the sharp clack of

firearms--then continuing boldly to advance, pouring shot after shot

into the massive animal until it toppled.

O'Hara's surprise was intense. "I did not know you had these weapons,"

he said, and the Elder smiled. It was a .45 revolver, the butt of it

worn smooth through countless decades of use, a type of gun that O'Hara

had never seen.

"Weapon?" said the Elder. "It is called Colt, not weapon. We have

always had them. Our people brought them when they came into these

mountains."

"Then you were not always here?"

It was the Elder's turn to be amazed. "Always? No--it was not the best

place to be always. We came here only to escape the sickness, in the

time of my fathers' fathers. Long ago."

"The sickness?"

"You are one of us, you are of our people," said the Elder. "We know

that because you use gunpowder, for we saw you kill the saber-tooth. If

you had used an atomic gun we would have fled, for they are stronger

than Colt--Colt cannot fight the atomic gun. But you are one of us, you

must know these things."

"I don't know them," said O'Hara. The children were by now busily

cutting up the giant bear, preparing it to take back to the caves. "I

came from beyond the Curtain--"

"What does this mean, beyond the Curtain?"

"Beyond the Atomic Curtain, which shields this continent from that

other world, my world, the Eastern Hemisphere. Beyond the oceans.

Europe, Asia, Africa."

"These sounds mean nothing to us--Europe, Asia, Africa. Are they other

mountains, perhaps along the Coast? We have not been there--it is too

far and the risk of death is too great."

"You never go down from these mountains?"

"None of us. It would be death from the sickness--or worse than death,

were we caught. Below the mountains is tabu for us. Were I to go, one

of my people would fire Colt at me. It is our law."

"But you permit others of your people to come here?"

"That is permitted, yet it has never happened until you came. We saw

you far above us, in that great flying thing you rode. We had never

seen that thing before, but there are stories--myths the older people

told when I was young--of the flying thing that men could ride across

the skies in, as the condor does. Did you come in it from another

mountain, beyond the regions of the Degraded?"

"From the north," said O'Hara. "Beyond the ice and the Curtain. But

what are the Degraded?"

"The atomic people, if you can call them people. Those who live in the

lowlands below the mountains."

"A different people?"

The Elder looked incredulous. "You must know these things. It is

impossible not to know these things."

"But I do not know them," said O'Hara. "Beyond the Curtain we know

nothing. Who are these atomic people and how are they different from

you? And the sickness you mention. Tell me--"

But it could not come all at once, not while there remained the chore

of cutting up the giant bear and gathering wood for the clan's fires

burning on the floor of the chasm. The Elder talked as he worked,

instructing the children--they were, O'Hara learned, considered the

clan's children, not the children of individual couples, for the idea

of the family had been expanded to include the entire clan. One family,

with the Elder heading it, two hundred of them living communally,

owning nothing. Even their weapons--Colts--were property of the clan,

handed down from generation to generation. They worked as a unit,

directed by the Elder, with strange little islands of technology in

their otherwise crude culture. For instance, they knew about ores--they

smelted metals and were expert in fashioning them, making the utensils

of their working lives, the bowls and pots and knives they used, and

the cartridges for Colt. Their mountains were rich in both copper

and iron, and when later O'Hara saw their diggings, the evidence was

there of long usage and a more advanced technology, much of which

the clansmen no longer understood. Among the Elder's most treasured

possessions was a large glass retort, once part of a rather extensive

chemical laboratory that now lay in ruins, its purpose no longer known

to the clansmen, who did not know the manufacture of glass. The Elder

considered his retort a sacred vessel--sacred through antiquity alone,

however.

"Our fathers who came here from the lowlands understood these things,"

he explained. "It was a magic, perhaps, that they needed there--perhaps

it saved them from the sickness. But we have not needed them and their

use is forgotten. We no longer know the ceremonies for them."

"This clan is the only one to escape the sickness of the lowlands?"

"No, there are others. Many of us came together from the lowlands,

fleeing together--some of us came here, others went to other ranges

there, and beyond there," said the Elder, pointing. "And beyond

there--many clans, but not so many as those who stayed in the lowlands

and were lost."

"You see these clans?"

They never saw them. They were related peoples, but without any

political or blood ties, for the constant incursion of the atomic

peoples--the Degraded--made any close association of these mountain

clans impossible. Always, the Elder said, the thousands of the Degraded

swarmed up through the valleys, searching for the mountain people,

hunting them.

"For them, the Degraded, there is never any work--they do not need

wood for fires or animals for food or copper for their utensils," said

the Elder. "There is no risk in their lives, other than the risk of

hunting us. They do not want to destroy us--they want only to take us

to replenish their blood, to halt the sickness. But we wish death to

mating with them. They are animals. Surely you know?"

"I do not know."

"They were like us once," said the Elder. "That is the story of my

fathers' fathers--they were like us once, when all of us lived in the

lowlands, the great plains toward the rivers. But that was in the first

years."

"What do you mean by the first years?"

The Elder tried to answer. "It was a time of great things and great

triumphs. No one was hungry and no one needed to hunt for food. Have

you seen from the flying thing the vast glistening colored objects

lying in the valleys? That is a part of it--that was left from the

first years. People lived in piles of stones and the sun provided them

with everything they needed. But it was long ago. It has no meaning

now, no real meaning that I understand. For something happened that had

to do with the sickness and our people fled from it. I had heard the

old men of the clan, when I was a child, thirty years ago, attempt to

explain what they remember their fathers telling them and they could

not make it clear to me."

"Thirty years ago. You were a child then?"

"Yes, thirty years ago. That is an old age, older than most."

"These children--?"

"Two and three--with us they mature slowly. Among the Degraded they are

old at twenty, older at twenty than I am at thirty."

"Tell me," asked O'Hara, "what is Nedra's age?"

"She has lived nine winters. This is the tenth of them."

O'Hara felt as if the earth had shuddered under his feet. Nedra

was ten--for a moment he thought that possibly they reckoned time

differently, but the Elder's own words refuted that reasoning--nine

winters! She was in her tenth year, mature--in many ways much more

mature than women of his own world at the mating age, certainly

without the protective claptrap of sentimentality and romantic

misconceptions. Was it, then, strange that the degenerated emotions

of old age were absent from these people? Passion and ferocity, which

were the attributes of youth, but not malice and tenderness. When the

life span was cut so short there was not time for these. Returning

later to his cavern, he entered with a sense of active guilt, of

shame, but the intricately carved wooden club was lying on the floor,

significantly, and Nedra was waiting with that look of adoration that

he now recognized as the adoration of a child's mind, but she was not a

child--she was magnificently dangerous, splendidly strong and quick,

knowing what she wanted, and without absurd squeamishness about it.

"I am waiting for you, O'Hara."

"Yes--I see you are. But never mind that club. We'll get along without

it--"

"How?" She asked it simply. She could not conceive of placid

submission, nor, after that, could O'Hara. It was another turning point.

What the Elder had meant by the first years was never made clearer,

but O'Hara, remembering the long-forgotten books of those musty Oxford

cellars--the books that had so fascinated him in school--concluded that

the first years meant the decades immediately after the establishment

of the Atomic Curtain, an historic milestone that these mountain

clansmen no longer understood, now lost to them after the rapid

succession of many generations, one each ten years. But concerning the

sickness of the lowlands, the Elder was better informed. For it was a

continuing thing, present among the atomic peoples even now, and the

constant dread and loathing of the clansmen.

"What they eat," said the Elder, "is abomination. It grows in the

lowlands in those immense systems of colored objects that are like

pipes--if you did not see them from your flying thing I will take

you to a peak from which you can see them. And these pipes are

contaminated, making their food a poisonous stuff--yet they no longer

have any other way to feed. Nor do they wish to feed in any other way.

For everything is done for them by atomic power--"

"Who does these things by this power for them?"

"These things are fixed. No one needs to do them."

"They are automatic?"

"We do not know your word, but no one needs to do things for the

atomic peoples. Everything is done. They have contrivances to work

for them--the colored pipes to grow their food, and the water that

they drink and that flows in these pipes they draw from the ocean that

is said to be beyond the mountains toward the west, but the water

also is contaminated. The earth itself--the soil of the lowlands--is

contaminated, soaked with atomic wastes. Their cities--"

"What about their cities?"

"None of us has seen them, but we have heard that they exist. Our

fathers' fathers told these things--once they built places out of

stones and metals, like mountains with many caves, but they fled from

them in the first years. That was before our people left. They were

driven by the sickness--"

"How does the sickness injure them?"

"It is in their get."

"Only in their get?"

"Only in their get--it does not injure those already born, but their

get become different. Each generation they become more and more like

animals. Undeniably animals, though once they were like us. Now their

arms are much longer than ours and their feet are different, their jaws

are thrust out, their heads are shaped oddly, sloping back above the

brows of their eyes--"

"Like apes?"

"Apes?" asked the Elder, puzzled.

"Never mind. You say this sickness comes from what they eat and drink

and the cities that they live in?"

"From everything that is about their lives. The Tubes, the Sun Beneath

the Earth--"

"What are these?"

"We do not know. We have never seen them. They were devised after the

first years, when our fathers' fathers fled. But the legends are that

the Tubes run everywhere beneath the crust of the earth, as the trails

lie across the mountains, and that somewhere among these Tubes there is

a Sun that glows, giving heat and light and power--and something else

that we do not understand, a strange protection, not against us, but

against a great evil--"

"The Curtain!"

"You know what this evil is?"

"Perhaps. And I'll learn more. But tell me one thing now--why did your

people flee this sickness?"

The Elder's dignity was impressive. "I've told you that--what happens

to their get. It is better to fight and to struggle for your life. Man

was not meant to exist, as a worm does, pallid and content beneath a

log."

And that was as close to an expression of religious belief as O'Hara

was to hear among these mountain clansmen. Security was evil in itself.

Considering this, O'Hara decided that in those first years these

clansmen who had fled the fat and effortless life of the atomic regions

had discovered that security had an inevitable price, and it had been

a price that they would not pay. They had turned their backs upon

it, fleeing from it, escaping the greatest of all scientific wonders

because of the greatest of all scientific mistakes--an unforeseeable

error that they grasped only by seeing its result, without

understanding of the cause. Yet they must have known it once.

O'Hara knew it.

Atomic contamination, never quite deadly, low enough to be tolerated,

nonetheless had wrought its havoc in the genes of the race.

It had reversed the process of evolution.

The people of the lowlands, the atomic peoples, were reverting,

returning toward the ape, and at a pace incredibly speeded up by some

mutation within the reproductive genes that forced maturity at ten

years of age, a generation every decade, ten to a century--twenty-seven

since the establishment of the Atomic Curtain! But the rate of

retrogression was immeasurably swifter than had been the slow climb

upward since the dawn of time. For with the reversal of the process

of evolution, an atomic disaster within the genes, had also come the

reversal of the law that only the fittest could survive--the perfect

atomic state, with security for all, was preserving and multiplying the

predominant strain, those who were unfit!

Even these mountain clans who had fled, they too had taken that first

short stride back toward the dawn. They had got back to the simplicity

of life and the magnificent stature of Cro-Magnon times. For even

here, remote from the pipe farms and the reservoirs of distilled and

contaminated sea water, the radioactive food and drink of the lowlands,

the dangerously hot power plants--even here there was always a degree

of radiation. O'Hara's scintillometer had shown .285 milliroentgens an

hour just before his craft had crashed--not dangerous, as veterans of

the International Patrol reckoned danger, but over a period of time a

factor never fully evaluated.

Adults at ten! Old men at thirty! And, as the Elder said, even sooner

in the lowlands.

The Elder had described the atomic peoples as animals--as apes--but

O'Hara was puzzled by these accounts of scientific achievement, the

atomic weapons, the vast pipe farms which were the sources of food, the

distillation of oceans, and the Curtain itself. Surely these were not

the product of inferior minds, and as surely there must be somewhere in

the lowlands another people, a superior people who had conceived and

who directed the operation of these superb contrivances. But if there

was such a people, the Elder did not know of them.

"The people of the mountains and the Degraded--there are no others," he

insisted. "There cannot possibly be others, for if they lived there,

they too would have the sickness."

O'Hara could not believe this. Yet he confessed it did not seem to be

a greater contradiction of the possible than that a cave-dwelling race

should employ gunpowder and understand the lightning properties of

petroleum.

The petroleum remained for him a goal to be attained. The Elder

was evasive, and Nedra, who would have told him anything she knew,

considered it a mystery she neither comprehended nor cared about.

"Why talk of their torches?" she demanded. "If we need them, they will

give them to us. Am I not enough to amuse you?"

"Yes, Nedra, but I want to know--"

"Are you really one of us, O'Hara? You ask questions that could

interest only an old man of thirty, yet you cannot be more than twelve.

You are restless, you are unhappy with me. I am not beautiful to you."

"No woman anywhere is quite as beautiful."

"There is something that you want. Is it babies, O'Hara? Soon we will

have them."

"For the clan, I suppose?"

"For the clan, of course. Would you like to take them with us and

leave the clan, go to another mountain? Is that what you want? But the

Degraded would catch us. Would you want your sons and daughter to breed

with the Degraded? No, we must stay with the clan and our babies must

be for the clan."

"Our babies," he said, for he had forgotten that. There would be

babies. And before he was an old man they would be older men. And

Nedra--Nedra would be gone.

"In the place that you came from in the flying thing, O'Hara," Nedra

was saying, "are the people there like me?"

"Not like you, Nedra. But they would admire you."

"As you admire me?"

"Yes."

Then, peremptorily, "Admire me, O'Hara, and let us begin to have our

babies."

The eternal antidote! Wherever women were, they had this cure for

restlessness. And there was something to it. He was not going to find,

on either side of the Curtain, a life more idyllic than this. They had

drawn a screen of skins across the mouth of the cavern and their log

fire gave sufficient light and warmth; they had eaten together and now

they were lying together on a heavy pad of furs, Nedra luxuriating in

the tigrish grace of her naked body. Was there more than this?

"Nedra," he said at last, "I've got to know about the torches."

"The Elder knows these things. Ask him."

"Where does he get the petroleum?"

"That is a secret word. I do not know it."

"The oil--the stuff that burns in them. The black water."

"Why do you need to know about the black water?"

"For my--for the flying thing."

"That makes it fly?"

"Yes, Nedra."

"You want to fly away again?"

"I want to fly, though perhaps not far away. Perhaps that can't be

done--not far."

"You wish to fly above the lands of the Degraded?"

"Perhaps."

"Then I will kill you."

"No," he said, "you won't. You must understand this, Nedra. As it is

your nature to love, it is my nature to fly."

"Then I have not been a strong mate for you. I have been too weak, but

I--"

"Leave the club where it is," O'Hara laughed. "And I'll talk no more to

you of torches."

But with the Elder he was finally more successful. It came about

through the Elder's reverence for the weapon he called Colt. The

mechanics of it had an almost ecstatic fascination for him. He would

take hours to explain the workings of each part, diagraming it in

the sand before the caves, stopping from time to time to recite some

victory he had won with it, a giant bear, a saber-tooth, a monster

ground sloth that had come wandering from the lowlands.

"And do you know what makes it eternal?" he asked O'Hara. "It is the

black water of our torches."

"I understand about the black water," said O'Hara instantly, determined

now to trade on the Elder's reverence. "For that is what takes my

flying thing into the air, like a bird."

"The black water does that?"

"When certain things have first been done to the black water. Would you

like to see it?"

The Elder drew himself erect, a gaunt six feet eight, his face turned

upward to the sky. "I would like to see the flying thing go up."

"Then I must have the black water."

"We will go to the place tomorrow."

"And we must boil it. We must build a machine, something like the

machines you use for smelting copper. Come into the cavern, I will draw

the parts for it in secret for you. I will show you on the walls of the

cavern how it must be done."

"We can make this machine?"

"It will take time. But if you can make the cartridges for Colt, you

can make this machine. We will do it together."

Using a pointed splinter of obsidian, O'Hara tediously worked out

the design for a rudimentary still, sufficient, he was certain, for

refracting kerosene. "This part must be copper," he explained to the

Elder. "A retort to contain the black water."

"I see it, O'Hara."

"And here we must have pipes. Like a hollow reed, like the barrel of

Colt. Can you do this?"

"It can be done. We will make a rod of clay and dip it into molten

copper. When it cools we will wash out the clay."

"That will do it. You must have a very hot fire here--I think that if

we spray black water on a bed of coals--with perhaps a bellows here--"

"You must draw that."

"Here it is. And we will need these coils--we will bend the copper

pipes for this--"

O'Hara rapidly continued drawing. The sketches were making some kind of

sense to the Elder.

"They are like the bright clear metal that I showed you in the old

place," he suggested, and O'Hara nodded--like the glass retorts in the

abandoned laboratory.

"This is the machine," he said. "The black water will become

colorless, and with it, then, the flying thing will soar into the sky.

But first we must have black water."

"We will go for it in the morning," said the Elder. "It will take two

days to reach the lake that has it. I must go now--your woman is angry.

Women do not like these secret things."

When the Elder left, Nedra seized O'Hara's arm. "It was evil of you to

make these drawings," she burst out, angry. "They are like the drawings

of women who design new pots. They are unmanly."

"You think I am unmanly, Nedra?"

"When you draw these things, yes."

"You think so, Nedra?" He moved backward quickly, seizing the carved

club and then walking very slowly toward her.

When at last it was over, and she turned sleepily on the bearskin at

his side, her voice, for once, seemed almost gentle. "We have begun our

babies, O'Hara. And I will never leave you now."

With dawn, the Elder marshaled his caravan for the journey to the

lake that had the black water--a natural pool of petroleum, O'Hara

felt certain. And Nedra, alone of all the women, was going. The Elder

had his say upon that issue--a scornful speech, addressed to O'Hara,

concerning the proper management of women. But Nedra ignored it. Her

arms were taut around O'Hara's neck, her face obstinately buried

against the brilliant blue of his jacket.

"She will delay us," the Elder insisted. "And we must travel swiftly

a great distance. We must cross the valley below us, and if there is

trouble we cannot wait for a woman to keep pace."

The atom curtain · 第 10 / 31 题