Former spacer Kevan "Mac" McDougal has spent the last two years stranded on the frozen planet Crucible. The AI that held Mac and the other survivors of past crashes captive within a power-dampening field is gone, but the challenge of making a life out of the harsh environment of Crucible remains. But when a League scout ship finally arrives, it brings news of a new threat rather than the promise of rescue. Mac must lead the survivors of the colony in a desperate fight against an insectoid alien race with its own plans for Crucible, plans that do not include the survival of its human inhabitants.