Cavalry captain Gabriel Lacey returns to Regency London from the Napoleonic wars, burned out, fighting melancholia, his career ended. His interest is piqued 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. At the same time, he struggles with his own transition 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.