The passage was deserted. Gavin slipped into the escape well which led from the engine room to the Nova's outer skin, clambered downward again. He stepped from the escape well softly into the engine room itself. At first he thought it was deserted. Then he discovered a guard posted beside the sealed door in the aft bulkhead. Gavin had never seen him before. He was a big Terran in coarse outer garments. He was facing half away from the T.I.S. agent, holding a dart-gun. Gavin slipped his fingers through his brass knucks. He edged cautiously from behind the Nova's cyclotron, crept up on the man with the stealth of a ferret. At the last moment, the fellow heard him and swung around. Gavin clipped him behind his ear with the weight of his shoulder back of the blow. The guard's head banged against the steel bulkhead. He slipped nervelessly to a sitting posture, tumbled sideways. His breath bubbled with a rattling sound from his mouth. Then he stopped breathing. Without bothering to check his pulse, Gavin turned to the control panel. The fuel gauge showed a comfortable surplus. Ears straining to catch any untoward sound, he slowly pulled down the lever which dumped the fuel, watched the gauge with a growing tensity of nerves. The level in the gauge dropped tantalizingly slowly, as the liquid fuel bubbled out of the tanks onto the surface of Jupiter to saturate the soil. It was still a half-inch from the empty symbol when he heard voices. Someone was descending the ladder into the engine room. Gavin's jaw set; his lips thinned. With his left hand he drew his dart-gun, but he didn't release the dumping lever. The gauge showed a three-eighths of an inch, then a quarter. A pair of boots descended into his range of vision followed by the legs and waist of a man. The man reached the deck, faced around and stared at the T.I.S. agent in astonishment. "Don't move!" began Gavin. Another voice from up the ladder barked "Drop that gun!" Gavin's eyes flashed upward. He saw a man's head, shoulder and arm through the circular ladder well. The man seemed to be lying on the deck above covering him through the opening with a dart-gun. Gavin dropped his own automatic. "Take your hand off that lever!" the man snapped. Gavin flicked his eye to the gauge. The last of the fuel was flowing from the tanks. He released the lever, straightened his shoulders. Let them do what they pleased to him now, he thought, they were too late. The Nova was grounded! The second man descended the ladder and the pair of them regarded him curiously. They were both big men, Terrans in baggy outer garments like the guard whose skull Gavin had cracked. "Who the hell are you?" asked the first man in a flat voice. These men were bad. They didn't play at it. They didn't try to be. It was etched in their cold eyes and tight mouths. Gavin moistened his lips. "Murdock. Third assistant-engineer."