US Marshal John Mason gains full custody of his son and is transferred to Sanctuary, a witness protection town that isn't on any map. When the town's first ever murder occurs, John's plans to reconnect with his boy are derailed by the investigation.

Andra Caleri gave up her old life a long time ago, but someone wants her out of Sanctuary - to pay. As accusations fly and John uncovers a conspiracy that stretches all the way to Washington, Andra's past comes back in a true test of the mercy she received. Can John give up what he wants the most to bring the truth to light?