"All I know about it is legend, the sort of tales that old women tell in the evenings. Many of our people have been taken there as prisoners in raids, but none has ever returned alive." Leaving Steve Brent in command in the control room for the moment, Gerry went aft to his quarters where he had a compact Tri-dimensional-cinema outfit. He was passing along one of the corridors on B-deck when he abruptly halted. A faint humming was coming from behind the closed door of the radio room! The _Viking's_ sending outfit was not strong enough to bridge the vastness of interplanetary space. Such outfits existed, of course, but only a small set had been installed on the space-ship because of the extra weight involved. The radio room had been closed and locked weeks ago. No one was supposed to have access to it except Steve Brent and Gerry himself. And yet--the unmistakable hum of a generator was coming from behind the closed door! Gerry cautiously tested the knob of the door. It gave under his hand. As he opened the portal a crack, he clearly heard the sharp murmur of the sending apparatus. Then he swung the door wide on its noiseless and well oiled hinges. A dim light gleamed across the room! A dark figure was crouched tensely over the table that held the sending set. At the moment Gerry could not see who it was. Two steps Gerry took into the room. Three steps. The rubberoid soles of his shoes made no sound. Then a crushing weight descended on top of his head! In the half second before he lost consciousness, he realized that there had been a second interloper in the radio room. Someone who had been crouching against the wall by the door, and who had slugged him as he passed. * * * * * When consciousness returned to Gerry Norton, he was lying alone on the floor of the darkened radio room. He sat up, and rubbed his aching head, and swore softly. There was no sign of the interlopers, nor any clue to their identity. The whole incident puzzled him. His assailants must have been from among the _Viking's_ crew. That was surprising enough in itself, but there was also the problem of motive. Why would anybody be sending a secret message when there was no receiving set within millions of miles? The thing just didn't make sense. Closing the radio room behind him Gerry went back to the control-room and drew Steve Brent aside. "Look here, Steve! I just found someone sending a secret message out over the radio, and got knocked on the head before I could see who it was." "You must have been reading some of those funny old Twentieth Century gangster yarns of evil deeds!" Steve grinned. "I'm serious. That really happened." Gerry snapped. The grin faded from Brent's freckled face. "Then it must have been Chester Sand," he said promptly. "Why do you say that?" Brent shrugged. "Because he's the only man aboard that I don't know too well to suspect."