London, 1816: Cavalry captain Gabriel Lacey returns to Regency London from the Napoleonic wars, burned out, fighting melancholia, his career ended. His interest is perked when he learns of a missing girl, possibly kidnapped by a prominent member of Parliament.

Lacey's search for the girl leads to the discovery of murder, corruption, and dealings with a leader of the underworld. Lacey faces his own disorientation upon transitioning from a soldier's life to the civilian world, redefining his role with his former commanding officer and making new friends--from the top of society to the street girls of Covent Garden.