At some point in the not too distant future, a mining and research colony is set up on one of Jupiter's moons, Io. Everything is ok, until a major earthquake (or whatever the Io equivalent is) destroys the communications array and puts the colony in danger of falling down the side of a canyon. In a desperate bid to escape destruction the colonists have to reactivate an abandoned space station and use it to try to get back to Earth. The events that take place on the trip , i.e. malfunctioning computers, a waning food supply and rogue weapons satellites, to name but 3, test the colonists to their limits.