Synopsis: An expedition discovers a star ship buried in the ice at the south pole. Scientists are dispatched to investigate and manage to launch it, but it causes a planet-wide flood. They manage to get the autopilot to bring the ship to its home port. Then they learn this was some kind of test, and they are to go on a quest, helping fallen worlds as they search with the promise that if they succeed, all will be put to rights on their home world. They are joined by several aliens and have many adventures.