rior we were. Rubber-clad soldiers moved about in the blue glow of
the globes sending down their heatless light from the ceiling. One sat
at a desk near the elevator. As I spied him a green light glowed in
front of him twice.

"They've got him, sir, bringing him in."

A low-toned order. The soldiers sprang to their post. A whirring
signal. At the other end of the room the steel wall began to move
upward, and water rushed in. A tremendous vibration shook the chamber:
a ponderous thudding. The water rose to the level of the balcony and
stopped. I looked at Bradley.

"We're beneath the surface, aren't we?" I asked. "How is it that the
water doesn't fill the room?"

"Pumps," he replied. "Tremendous pumps that draw the water out just as
fast as it comes in, and shoot it out again into the sea. We can
maintain any desired level in here."

Then I noticed that the black flood was rushing by beneath me at a
terrific rate.

Something bulked in the opening. Two tiny subs drew in, a black and a
green. The steel wall rushed down again, and the vibration ceased.
From the green craft heavy grapples extended, clutching the black,
enemy scout. I saw a gaping hole in the black boat's nose, where its
eye had been smashed.

Men were clambering over both vessels' hulls, tugging at the hatchway
fastenings. The black one flew open. I leaped to the deck. Bradley
after me, and jumped down into the hold.

In the little cubby-hole that was all the machinery left space for, a
pale-faced form in green-gray crouched against the wall. His eyes
stared in fear. A Russian, praise be. And not far from my size and
build.

"Off with his clothes, quick!" I yelled, stripping mine as I spoke.
Bradley looked at me queerly, and shrugged his shoulders. "Quick, man!
Everything depends on speed!"

He shook his head, as one who listens to the vaporings of an imbecile,
but turned to obey. I was standing there--naked, studying the
Easterner's face, his body. No scars. Good.

* * * * *

Jim turned to me, the prisoner's clothing in his hands. An exclamation
burst from him. He looked back at the trembling Russ, then at me. "My
God, Eric, how did you do it?" he asked.

I smiled. "All right, is it?"

"You're his twin; no, you're himself! If I'd had a drink to-day I'd be
sure I was seeing double. How on earth--you had no make-up, no time--"

I was sliding into the Red's gear as I talked! "I've trained all the
little muscl