The screen was blank!

Friday looked up with a grin from where he was kneeling before the k.n.o.b on the door of the cell. Ca.r.s.e saw that the k.n.o.b was of metal, centered in an inset square of some dull fibrous composition.

"This door has an electric lock, suh," the negro explained rapidly. "And things worked by electricity can often be short-circuited!"

Quickly and silently he had disconnected from the television projector the wire which led back through the ventilating slit in the wall, and now was holding its end with one hand while with the other he twisted out the screw which held in the k.n.o.b. "Anyway, won't hurt to try," he said, removing the screw and laying it on the floor. In another second the k.n.o.b lay beside it, and he was squinting into the hole where it had fitted.

"Be quick!" Ca.r.s.e whispered.

Friday did not answer. He was guessing at the location of the mechanism within, and trying to summon up all the knowledge he had of such things.

After a moment he bent one of the live ends of the wire he was holding into a gentle curve and felt his way down within the lock with it, carefully keeping the other end clear of all contacts.

Seconds went by as his fingers delicately worked--seconds that told terribly on Hawk Ca.r.s.e. For the screen was blank and lifeless, and there was no way of knowing how far the work in the laboratory had meanwhile progressed. In his mind remained each detail of the scene as he had viewed it last: the strapped-down figure, the approaching anesthetic cylinder, the knives lying in readiness.... How was he to know if one of those instruments were not already tinged with scarlet?

"Oh, be quick!" he cried again.

"If I can touch a live part of the lock's circuit," grunted Friday, absorbed, "there ought--to--be--trouble."

Suddenly currents clashed with a sputtering hiss, and a shower of sparks shot out of the k.n.o.b-hole and were instantly gone. Short-circuited! It remained to be seen whether it had destroyed the mechanism of the lock.

Friday dropped the hot, burned-through wire he was holding and reached for the k.n.o.b, but the Hawk had leaped into life and was ahead of him.

In a moment the k.n.o.b was in the door and its holding screw part-way in.

Gently the Hawk tried the k.n.o.b. It turned!

But they did not leave the cell--then. Ku Sui's voice was echoing through the room, more than a trace of irritation in its tone:

"Hawk Ca.r.s.e, you are beginning to annoy me--you and your too-clever black satellite."

Ca.r.s.e's eyes flashed to the ceiling. A small disklike object, almost unnoticeable, lay flat against it in one place.

"Yes," continued Ku Sui, "I can talk to you, hear you and see you. I believe you have succeeded in destroying the lock. So open it and glance into the corridor--and escape, if you still want to. I rather wish you'd try, for I'm extremely busy and must not be disturbed again."

Graven-faced, without comment Ca.r.s.e turned the k.n.o.b and opened the door an inch. He peeped through, Friday doing so also over his head--peeped right into the muzzles of four ray-guns, held by an equal number of coolie-guards waiting there.

"So that's it," Friday said, dejectedly. "He saw me workin' on the lock an' sent those guards here at once. Or else had them there all the time."

The Hawk closed the door and considered what to do. Ku Sui's voice returned.

"Yes," it sounded metallically, "I've an a.s.sistant posted here who's watching every move you make. Don't, therefore, hope to surprise me by anything you may do.

"Now I am going to resume work. Reconnect the screen: I've had the burned-out fuse replaced. If you won't, I'll have it done for you--and have you so bound that you'll be forced to look at it.

"Don't tamper with any of my hearing and seeing mechanisms again, please. If you do, I will be forced to have you destroyed within five minutes.

"But--if you'd like to leave your cell, you have my full permission. You should find it easy, now that the lock is broken."

The voice said no more. Ca.r.s.e ordered Friday harshly:

"Reconnect the screen."

The negro hastened to obey. His master's gray eyes again fastened on the screen. Fiercely, for a moment, he smoothed his bangs.

The laboratory flashed into clear outline again. There was the shaft of white light; the operating table, full under it; the anesthetic cylinder, the banks of instruments, the sterilizers with their wisps of steam curling ceaselessly up. There were the efficient white-clad a.s.sistant-surgeons, their dull eyes showing through the holes in their masks. And there was the black figure of Ku Sui, an ironic smile on his lips, and before him the resigned and helpless form of Eliot Leithgow.

The Eurasian gestured. An a.s.sistant found the pulse in Leithgow's wrist, and another bent over him in such fashion that the prisoners could not see what he was doing. Ku Sui too bent over, something in his hands. The prelude to living death had begun....

At that moment Hawk Ca.r.s.e was a different man, recovered from the weakness that had made him cry out at his friend's imminent destruction a short time before. The old characteristic fierceness and recklessness had come back to him; he had decided on action--on probable death. "I've been too cautious!" he exclaimed violently in his thoughts.

"Friday!" he whispered sharply to the negro, going close.

"Yes, suh?"

"Four men outside--a sudden charge through that door when I nod. We'll die, too, by G.o.d! Willing?"

Friday was held by the man's iron will to succeed or die. Without hesitation he whispered back:

"Yes, suh!"

Their whispers had been low. Dr. Ku Sui had not been warned, for the screen still showed him bending over his victim.

"You'll open the door; you're nearest. I'll go through first," the Hawk murmured, and smiled at the loyalty behind the promptness of his man's grin of understanding.

Then both smiles faded. The muscles of the negro's huge body bunched in readiness for the signal as tensely he watched the flaxen-haired head close to him.

Suddenly it nodded.

The door swung wide and white man and black went charging out.

And immediately there burst in their ears the furious clanging of a general alarm bell, sounding throughout the whole building!

CHAPTER XI

_Trapped in the Laboratory_

In his carefully welded plot-chain, Ku Sui left one weak link, though he was not aware of it at the time. For it would not appear save by the testing of it, and he had not expected it to be tested. Ca.r.s.e acted recklessly; perhaps, if cold reason be applied to his move, senselessly.

Dr. Ku had not thought he would dare make the break he did. But the adventurer did dare, and the loophole, the weak link, was exposed.