There were perhaps three hundred prisoners here, Luke guessed, and a guard allotted to each squad of fifteen men. Not many guards for so large a number of convicts--but enough. The weird gravity of Vulcan had taken care of that, and the flashlight things they always carried--queer lights that would instantly neutralize the insulating property of his clothing and render a man helpless. * * * * * Luke was working high up on the slope, with rock drill and pick. The group to which he had been assigned was composed entirely of new prisoners, mostly white men, but with a few blacks and one coppery-skinned drylander of Mars. Whimpering, hopeless creatures, all of them; not worth his notice. All day he labored without speaking to any of them and the quantities of ore he removed gave mute evidence of his tireless vigor. If Kulan, the giant Martian guard, took any notice of it he gave no sign. During the sleeping period, which they persisted in calling night, things were different. No guards were needed in the escape-proof huts and there was some surreptitious fraternizing among the prisoners. As long as they made no undue noise, they were left to their own devices. But for the most part they went to sleep heavily and wordlessly as soon as they flung into their bunks. A broken-spirited lot. Luke saw men suffering from some horrible malady that made them cough and scream and bleed from nose and mouth. Old-timers, these were, men who had survived for as many as three of four months. He saw them, in their agony, beg the guards for merciful death; heard the brutal laughter of their tormentors. Only when they were no longer able to rise from their bunks were they put out of their misery by one of the singing darts from the senior guard's gun. Novak had it, this malady known as X.C.--Novak, the scar-faced, yellow-fanged rat who occupied the bunk beneath Luke's and who talked to him in hoarse whispers long after the others had gone to sleep. It was from Novak that Luke was learning, and the knowledge he gained by listening to the doomed man served only to intensify the flame of hate that smoldered deep in his barrel-like chest. After three red-lit days of grueling labor and three similarly red-lit nights of listening to Novak, he reached the grudging conclusion that escape from this place was impossible. With this conviction there came to him a deeper bitterness and the resolve that he, Luke Fenton, would have his revenge before he went the way of the rest. Perhaps the law had him for keeps this time--it certainly seemed so; but he'd leave his mark on its representatives yet. * * * * * At inspection preceding the next labor period, Luke began doing things. The prisoners were lined up and the guards were parading the line, reassigning them to new working squads, which were shifted and rearranged every third day. Kulan, the big Martian, selected Luke.