The descendants of Expatria's first colonists from Earth have rejected technology. When Mathias Hanrahan, heir to the primacy of Newest Delhi, wants to reintroduce the old ways he is framed for his father's murder and forced to flee.

Recruited by a research team which is trying to relearn the ancient technologies, he goes to work for them, and against a background of impending war, Mathias discovers that strange messages are coming from space.