Carefully they made their few preparations, and Clee, again by acting, indicated to one of the animal-men what he wanted to do. He seemed to make himself well understood, for without hesitation the creature lay face down on the floor. The others all gathered around as Clee bent over it, and Jim scanned their faces closely for any sign of suspicion or resentment. Seeing none, he told Clee to start; then held his breath in awful suspense. The disk appeared near the surface, and with a quick slice Clee made his first incision. With the cut, the prone slave bucked and snarled. Clee murmured soothing words to it in English, and, as the creature quieted down, made another cut. Again came the bucking and throaty protest; and this time, to Jim's dismay, he saw in the bestial faces of the animal-men around them a sympathetic swing of emotional protest. A little more, now; and Clee would be able to take the disk out; but would the slaves restrain themselves until then? Again Clee allowed the brute body under him to calm down. Then, as he was about to cut once more, from somewhere above in the space ship came the piercing scream of a woman. Something was happening to Vivian. * * * * * Clee half started to rise, to run to her aid, but he forced himself to be reasonable. Weaponless, visible, he could never hope to rescue an invisible girl from someone he couldn't even see. He was on the point of making valuable allies; in just a few moments more--! He decided to hurry through with the job he had undertaken. All below had heard the scream. The circle around him was shifting uncertainly, and peculiar sounds were coming out of the brutes' twisting mouths as he bent again over their fellow on the floor. Clee's hand was trembling like an aspen leaf as he prepared to make the next incision. He was completely unnerved, and with the utmost efforts of his will he was unable to control the nailfile. And he had to hurry! He sliced as straight as he could at the bleeding lump; the slave moved; and the point of the file slipped deep into the creature's flesh! At that, with a snarling growl the brute below arched from the floor and flung Clee sprawling. From all around the circle came menacing growls as the bleeding animal-man lumbered to its feet and came after him in a definite attack. Jim, not at that moment the center of their attention, pushed one of the slaves in the way of the charging brute and the two of them half fell; and before they could recover their balance Clee was on his feet making after Jim to the steps that led up out of the room. "Up!" came Jim's shout. "Fast! We've made them enemies!"