The crew of Moya stop at the ancient site of a great siege, where Peacekeeper forces once negotiated surrender to a vastly superior army. Then, in the midst of this tranquility, the impossible happens. Through a freak combination of Stark's ethereal presence, and a mysterious tear in the fabric of time, Crichton and his comrades are thrust back into the past. Materialising in the midst of the ancient siege, they accidentally change the course of events. Now as time grows short, they must discover how to set right what once went wrong - before they become history, too.