"Report from hospital," said the radio. "Psychotic escaped in plane. Give warnings. The plane will be identified later; its owner is undergoing a serious operation and no records are immediately available. Be advised." "That must be it," said Handel practically. "He's out of all accepted zones and he hasn't got any right to hover over a residential district. Call him, Pete." Petersen aimed his short beam radio antenna in the general direction of the disputed plane. "Calling Monoplane of class ten," he said into the mike. "You with the brown body and blue wings. Can y' hear me?" Harshly a voice answered. "We hear. What is it?" "Sorry," said the pilot, "but you're hovering over a residential area. That's not allowed. What's your number, pilot?" "I have no number," said the voice, "and I have no license. Stand off or take the consequences!" "It's him--the psycho," hissed Petersen to Handel. "Call HQ on your set while I keep him busy." "Right," snapped the engineer, tuning in the traffic center. The pilot turned to his set, his brow wrinkled. How do you handle a psycho? Humor him. "What was that you said?" asked Petersen, smooth as silk. "Stand off, you fool, or take the consequences! I'll give you five seconds to get away." "Wait," said Petersen. "Why don't you--" Then he gasped, as his plans crumbled. The psycho's ship had winged over with terrible speed and was heading for his ship nose-on. "Stop!" he shrilled into the mike, his hand on the throttle. Then he sent his own plane into a loop that made his bones bend, and streaked for altitude, with the demon plane and its demon pilot on his tail. "I warned you," ground out of the speaker. "You'll do well to tell the world that there's one man alive who's not afraid to kill or be killed to achieve his ends. Spread the word, friend!" And, when Petersen looked around, the plane was a vanishing speck in the north, as he watched it reach the blending point and vanish in the sky. Handel, gibbering in a corner of the traffic ship where the last loop had flung him, cried, "What happened to it?" "I don't know," said the pilot soberly. "Did you get HQ?" "Yes, but the loop smashed my set. What do we do now?" "Fly back, but fast," said Petersen, giving his ship the gun. "Pete," said Handel. "Yeah?" "What do we do with a thing like that? I mean how do you finally get rid of them?" "I don't know," said the pilot slowly. "Lock them up once you catch them, I suppose." "Catch _that_? He tried to ram us! As he said--he's not afraid to kill or be killed." The engineer shuddered. "Do you think," he asked, "we'll have to kill him?" Petersen frowned. "I hope not," he said, his eyes ahead of him as he prepared to land. "But if there's no other way--what else can we do?" "How long since they killed a man--purposely, I mean?" The ship was rolling to a stop. "I dunno. Maybe a hundred years; maybe more. And who that was, I don't know either."