II

On the way back to the Med Ship, Calhoun stopped at another place

where, on a grass-growing planet, there would have been green sward.

There were Earth-type trees, and some native ones, and between them

there should have been a lawn. The trees were thriving, but the

ground-cover plants were collapsed and rotting.

Calhoun picked up a bit of the semi-slime and smelled it. It was

faintly sour, astringent, the same smell he'd noticed when he opened

the airlock door. He threw the stuff away and brushed off his hands.

Something had killed the ground-cover plants which had the habit of

killing Earth-type grass when planted here.

He listened. Everywhere that humans live, there are insects and birds

and other tiny creatures which are essential parts of the ecological

system to which the human race is adjusted. They have to be carried to

and established upon every new world that mankind hopes to occupy. But

there was no sound of such living creatures here.

It was probable that the bellowing roar of the Med Ship's emergency

rockets was the only real noise the city had heard since its people

went away.

The stillness bothered Murgatroyd. He said, "_Chee!_" in a subdued

tone and stayed close to Calhoun. Calhoun shook his head. Then he said

abruptly:

"Come along, Murgatroyd!"

He went back to the building housing the grid controls. He didn't look

at the spaceport log this time. He went to the instruments recording

the second function of a landing-grid. In addition to lifting up and

letting down ships of space, a landing-grid drew down power from the

ions of the upper atmosphere and broadcast it. It provided all the

energy that humans on a world could need. It was solar power, in a way,

absorbed and stored by a layer of ions miles high, which then could be

drawn on and distributed by the grid. During his descent Calhoun had

noted that broadcast power was still available. Now he looked at what

the instruments said.

The needle on the dial showing power-drain moved slowly back and forth.

It was a rhythmic movement, going from maximum to minimum power-use,

and then back again. Approximately six million kilowatts was being

taken out of the broadcast every two seconds for half of one second.

Then the drain cut off for a second and a half, and went on again for

half a second.

Frowning, Calhoun raised his eyes to a very fine color photograph on

the wall above the power dials. It was a picture of the human-occupied

part of Maya, taken four thousand miles out in space. It had been

enlarged to four feet by six, and Maya City could be seen as an

irregular group of squares and triangles measuring a little more than

half an inch by three-quarters. The detail was perfect. It was possible

to see perfectly straight, infinitely thin lines moving out from the

city. They were multiple-lane highways, mathematically straight from

one city to another, and then mathematically straight--though at a new

angle--until the next. Calhoun stared thoughtfully at them.

"The people left the city in a hurry," he told Murgatroyd, "and there

was little confusion, if any. So they knew in advance that they might

have to go. They were ready for it. If they took anything, they had it

ready packed in their cars. But they hadn't been sure they'd have to go

because they were going about their businesses as usual. All the shops

were open and people were eating in restaurants, and so on."

Murgatroyd said, "_Chee!_" as if in full agreement.

"Now," demanded Calhoun, "where did they go? The question's really

where could they go! There were about eight hundred thousand people in

this city. There'd be cars for everyone, of course, and two hundred

thousand cars would take everybody. But that's a lot of ground-cars!

Put 'em two hundred feet apart on a highway, and that's twenty-six

cars to the mile on each lane. Run them at a hundred miles an hour on

a twelve-lane road--using all lanes one way--and that's twenty-six

hundred cars per lane per hour, and that's thirty-one thousand ... two

highways make sixty-two ... three highways.... With two highways they

could empty the city in under three hours, and with three highways

close to two. Since there's no sign of panic, that's what they must

have done. Must have worked it out in advance, too. Maybe they'd done

it before it happened ... whatever it was that happened."

* * * * *

He searched the photograph which was so much more detailed than a map.

There were mountains to the north of Maya City, but only one highway

led north. There were more mountains to the west. One highway went into

them, but not through. To the south there was sea, which curved around

some three hundred miles from Maya City and put the human colony on

Maya on a peninsula.

"They went east," said Calhoun presently. He traced lines with his

finger. "Three highways go east; that's the only way they could go

quickly. They hadn't been sure they'd have to go but they knew where to

go when they did. So when they got their warning, they left. On three

highways, to the east. And we'll follow them and ask what the hell they

ran away from. Nothing's visible here!"

He went back to the Med Ship, Murgatroyd skipping with him.

As the airlock door closed behind them, he heard a click from the

outside-microphone speakers. He listened. It was a doubled clicking,

as of something turned on and almost at once turned off again. There

was a two-second cycle, the same as that of the power drain. Something

drawing six million kilowatts went on and immediately off again every

two seconds. It made a sound in speakers linked to outside microphones,

but it didn't make a noise in the air. The microphone clicks were

induction; pick-up; like cross-talk on defective telephone cables.

Calhoun shrugged his shoulders almost up to his ears. He went to the

communicator.

"Calling _Candida_--" he began, and the answer almost leaped down his

throat.

"_Candida_ to Med Ship. Come in! Come in! What's happened down there?"

"The city's deserted without any sign of panic," said Calhoun, "and

there's power and nothing seems to be broken down. But it's as if

somebody had said, 'Everybody clear out' and they did. That doesn't

happen on a whim! What's your next port of call?"

The _Candida's_ voice told him, hopefully.

"Take a report," commanded Calhoun. "Deliver it to the public health

office immediately you land. They'll get it to Med Service sector

headquarters. I'm going to stay here and find out what's been going on."

He dictated, growing irritated as he did so because he couldn't explain

what he reported. Something serious had taken place, but there was no

clue as to what it was. Strictly speaking, it wasn't certainly a public

health affair. But any emergency the size of this one involved public

health factors.

"I'm remaining aground to investigate," finished Calhoun. "I will

report further when or if it is possible. Message ends."

"What about our passenger?"

"To the devil with your passenger!" said Calhoun peevishly. "Do as you

please!"

* * * * *

He cut off the communicator and prepared for activity outside the ship.

Presently he and Murgatroyd went to look for transportation. The Med

Ship couldn't be used for a search operation; it didn't carry enough

rocket fuel. They'd have to use a ground vehicle.

It was again shocking to note that nothing had moved but sun shadows.

Again it seemed that everybody had simply walked out of some door or

other and failed to come back. Calhoun saw the windows of jewelers'

shops. Treasures lay unguarded in plain view. He saw a florist's shop.

Here there were Earth-type flowers apparently thriving, and some

strange beautiful flowers with olive-green foliage which throve as well

as the Earth-plants. There was a cage in which a plant had grown, and

that plant was wilting and about to rot. But a plant that had to be

grown in a cage....

He found a ground-car agency, perhaps for imported cars, perhaps for

those built on Maya. He went in and from the cars on display he chose

one, an elaborate sports car. He turned its key and it hummed. He drove

it carefully out into the empty street, Murgatroyd sitting interestedly

beside him.

"This is luxury, Murgatroyd," said Calhoun. "Also it's grand theft. We

medical characters can't usually afford such things. Or have an excuse

to steal them. But these are parlous times, so we take a chance."

"_Chee!_" said Murgatroyd.

"We want to find a fugitive population and ask what they ran away from.

As of the moment, it seems that they ran away from nothing. They may be

pleased to know they can come back."