Hawk Carse said nothing. With eyes ever-watchful for sign of a trick or a trap in the apparently deserted laboratory, he quickly unbuckled the bands that held Leithgow to the operating table. Friday lifted the scientist to the floor, where he stretched weakly. The adventurer smiled faintly, then his eyes went cold and serious. Crisply he said: "We came, yes--but now I think we're trapped. There'll be men outside each of these four doors. The bolts may hold them a while, but eventually they'll get through. We must look for further weapons. If only there were better light! Friday," he ordered, "look for a switch. _Ah!_" With a thud and a booming reverberation a systematic battering had begun on the metal door through which they had entered. It quivered visibly and rang as the powerful blows from the other side bludgeoned into it, and evenly spaced, shrewdly delivered at the vital middle point. _Whrang, whrang_--even strokes, ringing throughout the barred laboratory--_whrang ... whrang_.... And then a similar piece settled into clanging routine on another door; then on the remaining two. The bolts holding them jumped with each deafening thud. Friday scowled, forgot to search farther for the switch, took a few short, indecisive steps, and then stood still again, looking questioningly at his master. The Hawk stood silent also, smoothing the bangs of flaxen hair above one temple, his face knit in concentration. He had been afraid they would use the great projector on the door, and had been somewhat cheered by the reflection that they dared not, for fear of destroying the contents of the laboratory, especially the irreplaceable brains. But this was worse; Ku Sui was without question directing their efforts now. And that being the case, he could expect to see one door after another battered down--and then a concerted, four-point rush which would end everything.... * * * * * Eliot Leithgow said the extraordinary thing that pointed a way out. "May I suggest," he said mildly, "that we try to get Dr. Ku Sui's brains to help us?" "What do you mean?" The older man smiled, a little sadly. "Those brains--they once were friends of mine. It's possible they'll answer our questions. It won't hurt to try. We'll ask them how it might be possible to get out." Hawk Carse cried: "Eliot, you've got it! There is a chance!" But the negro shivered. The brains stood for magic, for ghosts--for awful, unknown things he wanted nothing to do with. Carse shoved back the screen concealing the infamous device. "We know where this switch is, at least. If only the current's not been turned off!" "Probably not," the Master Scientist said, out of his own technical thought-train. Friday hung back, loath to be concerned. He looked askance at the thing, his open mouth a small round circle.