Mysterious radio signals were being received from the planet Uranus, and Earth's leading scientists decided that a complete investigation was needed. For the first time, the U.N.E.X.A. planned a two-ship expedition, under the overall command of Chris Godfrey. Serge, Morrey and Tony were of course included, and four other astronauts made up the crew of the two ships.At first the signals made little difference to them, except that they produced violent headaches if listened to for more than a few seconds. But when Chris awoke after a spell of hypothermia and tried to call the other ship he was horrified to hear the sinister sounds from Uranus on the wavelength which connected the two ships with each other and both of them with Control, back on Earth...