And now Don knew that he was to die by the same hand that had killed his father. And Fred was through with him. The boy had helped to mine the gems, but his uncle had never intended that he should live to share them. That was why Uncle Fred had been drinking all day--to bolster up his courage to do deliberate murder. He raised the gun an inch. Don saw his finger tighten on the trigger. He closed his eyes, knowing that it would be all over in a moment. The paper-thin walls of the hut vibrated with the thunderous crash of an electronic pistol. Donald's jaw went slack. For a paralyzing second he could only gape at his uncle. The man had uttered a choking cry, his fingers loosening the gun. Then he pitched to the floor in a limp heap. In the open doorway stood a bullet-headed, brown-eyed man, holding a still-glowing electronic pistol. Over his shoulder peered a bearded, thick-lipped companion. * * * * * Bullet-head shifted his gaze to the boy. "Glad we showed up?" he asked, grinning. "Sure am. Thanks," said Don, eying the two men closely. They weren't settlers nor native-born sons of settlers. For the strangers walked with difficulty. They had yet to learn the gliding stride that was second nature to Don. And their complexions had never been won on Mars. "You must be Don," said Bullet-Head. "Right," said Don shortly. "What's your tag?" "Call me Pete. I heard about you from your uncle last time he was in Strada." Strada was the diamond center of Mars, Don knew. His uncle had been there a month ago with some specimens. There were only three kinds of people in Strada, the boy thought; business men, police and thieves. Hastily he ruled out the first two. His uncle must have told too much about his pay-load. These men had decided to cash in before it had reached a civilized city. Pete's brown eyes wrinkled. "Right, son," he said amiably. "We're here for the diamonds. Consider yourself lucky to be alive. Now just keep your mouth shut and pack that lizard of yours. We're going to Propontis." Don didn't ask any more questions. While he was filling the water tanks from their stores he thought with desperate clarity and speed. They were city men--earthmen, and could have hoofed it all the way. He knew how an Iguana could go sullen and completely intractable if it were mishandled; that, he guessed, was what had happened to the outlaw's pack-lizards. From the thin crust of sand on their boots the boy guessed that they hadn't had to walk more than a few miles. Don turned, and caught a glance that the two outlaws exchanged. In that look the boy read an answer to any other question in his mind. Don knew then that he had escaped death at his uncle's hands only to face it eventually from these two. Pete eyed him quizzically. "Let's get going," said the outlaw. "We'll put some distance between us and this shack before we camp for the night."