Humanity has found a way across the stars. It has yet to learn where the road leads.
The ancient relics recovered from Earth reveal a network of routes beyond anything human science can explain. Aboard the Caelus, Dr Mistral "Misty" lvarez and Commander Richard Richardson must discover whether those routes can carry a ship-and bring its crew home.
Every successful test raises the stakes. Behind the secrecy of the lunar programme, political ambition is gathering around a technology nobody understands. For Rich, who has already lost a friend to orders that should never have been given, the pressure is painfully familiar.
As he and Misty grow closer, an unmanned expedition returns with images of something vast and broken in the distant darkness. Something built. Something that still responds.
The newly formed Foldline team must prepare to follow.
But a route that opens is no promise of a safe return.