Jon Baird worked steadily in the _Niccola's_ radar room. He was one of those who hoped that the Plumies would not prove to be the natural enemies of mankind. Now, it looked like this ship wouldn't find out in this solar system. There were plenty of other ships on the hunt. From here on, it looked like routine to the next unvisited family of planets. But meanwhile he worked. Opposite him, Diane Holt worked as steadily, her dark head bent intently over a radar graph in formation. The immediate job was the completion of a map of the meteor swarms following cometary orbits about this sun. They interlaced emptiness with hazards to navigation, and nobody would try to drive through a solar system without such a map. Elsewhere in the ship, everything was normal. The engine room was a place of stillness and peace, save for the almost inaudible hum of the drive, running at half a million Gauss flux-density. The skipper did whatever skippers do when they are invisible to their subordinates. The weapons officer, Taine, thought appropriate thoughts. In the navigation room the second officer conscientiously glanced at each separate instrument at least once in each five minutes, and then carefully surveyed all the screens showing space outside the ship. The stewards disposed of the debris of the last meal, and began to get ready for the next. In the crew's quarters, those off duty read or worked at scrimshaw, or simply and contentedly loafed. Diane handed over the transparent radar graph, to be fitted into the three-dimensional map in the making. "There's a lump of stuff here," she said interestedly. "It could be the comet that once followed this orbit, now so old it's lost all its gases and isn't a comet any longer." * * * * * At this instant, which was 04 hours 25 minutes ship time, the alarm-bell rang. It clanged stridently over Baird's head, repeater-gongs sounded all through the ship, and there was a scurrying and a closing of doors. The alarm gong could mean only one thing. It made one's breath come faster or one's hair stand on end, according to temperament. The skipper's face appeared on the direct-line screen from the navigation room. "_Plumies?_" he demanded harshly. "_Mr. Baird! Plumies?_" Baird's hands were already flipping switches and plugging the radar room apparatus into a new setup. "There's a contact, sir," he said curtly. "No. There was a contact. It's broken now. Something detected us. We picked up a radar pulse. One." The word "one" meant much. A radar system that could get adequate information from a single pulse was not the work of amateurs. It was the product of a very highly developed technology. Setting all equipment to full-globular scanning, Baird felt a certain crawling sensation at the back of his neck. He'd been mapping within a narrow range above and below the line of this system's ecliptic. A lot could have happened outside the area he'd had under long-distance scanning.