"Where?" I whispered.
We stopped at a corner. An entryway was here. Snap pulled me into it.
I could feel him quivering with excitement.
"What is it?" I demanded in a whisper.
"We're being followed. Did you hear anything?"
"No!" Yet I thought now that I could hear something. Vague footfalls.
A rustling. And a microscopic whine, as though some device were within
range of us.
Snap was fumbling in his pocket. "Wait! I've got a pair of low-scale
detectors."
He put the little grids against his ears. I could hear the sharp
intake of his breath. Then he seized me, pulled me down to the metal
floor of the entryway.
"Back, Gregg! Get back!" I could barely hear his whisper. We crouched
as far back into the doorway as we could get. I was armed. My official
permit for the carrying of the pencil heat ray allowed me always to
have it with me. I drew it now. But there was nothing to shoot at. I
felt Snap clamping the grids on my ears. And now I heard something! An
intensification of the vague footsteps I had thought I heard before.
There was something following us! Something out in the corridor there
now! The corridor was dim, but plainly visible, and as far as I could
see it was empty. But there was something there. Something invisible!
I could hear it moving. Creeping toward us. I pulled the grids off my
ears.