"He murdered Zinder and Morrie Grover," I said in conclusion. "He means to kill two more of our party in order to insure enough water for the return trip. You could easily be a candidate." Joel listened, bewildered, to all I said, about finding the paper in Morrie's helmet air valve, about Axel knowing he had tampered with the machinery in Willy's capsule, and how Spartan had unfastened my safety line when I brought Morrie's body from the top of the Jehad. "I--I can't believe it," he said. "You're making it up." "Why should I?" I asked. "For the same reasons you're attributing to Dr. Spartan," he said. "You want to kill him so there'll be enough water. Maybe you want to kill me, too." "Damnit," I said, "we don't want to kill anybody. There may not be enough water to keep us from being thirsty, but there's enough to keep us from dying. I'm willing to suffer to avoid murder. That's why I'm planning to arrest Spartan." "Arrest! It's mutiny! When you get back to the earth there'll be a lot to answer for, Drake." "Then we'll have to arrest you, too," I said. "The rest of us--Axel, Gail and I--know the score, Warner. I've tried to explain it to you. If we can't trust you--" "Now just a minute! I didn't say that." "Not in so many words," I told him. I put my hand on the butt of my automatic pistol. His eyes followed the move. There was fear in his face. "I don't know what to do," he confessed. "Do nothing," I said. "That's all I ask." He gulped. He seemed a little relieved. "I don't see how I _can_ do anything," he replied. "Stand up!" I said. He looked frightened again. "What are you going to do?" "I'm taking your gun," I said. "Just to make sure you won't try anything." He stood up and I made him turn around. Then I took his gun. "You'll sleep in the lower cabin tonight," I told him. "Gail and I will take turns doing guard duty." * * * * * The next morning, Dr. Joel was a very subdued man. He ate breakfast silently and then volunteered to tidy up the cabin. He went about his tasks eagerly, anxious to please. All of the truckling he had done for Dr. Spartan now seemed to be transferred to Gail and me. About noon the Mars-car rolled in. I had been waiting for the arrival in my spacesuit and, as soon as it came within view, I slipped my helmet over my shoulders, sealed it and went out to meet them. The car bumped over the causeway and came to a stop at the base of the ramp. Spartan, holding the rifle in his hand, was standing in the locks. Axel was at the controls, putting on his helmet. Presently Axel entered the locks. Then both men jumped out to the ground. "Help Ludson with the samples, Drake," Spartan ordered. As he turned his head to gesture, I brought my automatic into view. "You're under arrest, Dr. Spartan," I said. Axel's mouth, which I could see through the glass of his helmet, gaped with surprise as he heard my words in his earphones. "What's the meaning of this?" Spartan cried.