The skipper tilted back his helmet and said beseechingly: "Scratch my head, will you?" When Patrolman Willis reached out his hand, the skipper revolved his head under it until the itchy place was scratched. Most men itch instantly they are unable to scratch. The skipper's space gloves were sprouting whiskers of moisture-frost now. "Thanks," he said gratefully. "What are you going to do, sergeant?" "Open communication with 'em," said the sergeant, heavily. The skipper waited. Opening communication with someone who shoots on detector-contact may be difficult. "I figure," rumbled the sergeant, "they're a lot like delinks. A cop can figure how they think, but they can't figure how a cop thinks." "Such as?" asked the skipper. "They can't understand anybody not tryin' to be important," said Sergeant Madden. "It baffles 'em." "What's that got to do with the people on the _Cerberus_?" demanded the skipper. "It's our job to get them and the _Cerberus_ back on the way to port!" "I know!" conceded Sergeant Madden, "and the girl my son Timmy's going to marry is one of them. But I don't think we'll have much trouble. Have you got any multipoly plastic on the _Aldeb_?" The skipper nodded, blankly. Multipoly plastic is a substance as anomalous as its name. It is a multiple polymer of something-or-other which stretches very accommodatingly to a surprising expanse, and then suddenly stops stretching. When it stops, it has a high and obstinate tensile strength. All ships carry it for temporary repairs, because it will seal off anything. A one-mill thickness will hold fifteen pounds pressure. Ships have been known to come down for landing with bubbles of multipoly glistening out of holes in their hulls. A salvage ship, especially, would carry an ample supply. A minor convenience in its use is the fact that a detonator-cap set off at any part of it starts a wave of disintegration which is too slow to be an explosion and cleans up the mess made in its application. "Naturally I've got it," said the skipper. "What do you want with it?" Sergeant Madden told him. Painfully. Painstakingly. "The tough part," said the skipper, "is making 'em go out an ejector tube. But I've got fourteen good men. Give me two hours for the first batch. We'll make up the second while you're placing them." Sergeant Madden nodded. The skipper went into the lock and closed the door behind him. After a moment Patrolman Willis saw him wading through the incredibly delicate and fragile gas-ice crystals. Then the _Aldeb_'s lock swallowed him. * * * * *