When Captain Gabriel Lacey finds himself standing over a dead body in Brighton Pavilion, bloody sword in hand and no memory of how he got there, he immediately fears he is a murderer.

The dead man is Colonel Hamilton Isherwood, a man Lacey clashed with after the battle of Salamanca in Spain seven years before. As Lacey tries to piece together the events of the previous night, he discovers he'd promised to help a Quaker gentleman find his missing son, and that the Society of Friends might know far more about his strange night out than anyone else.

With the help of Brewster, Grenville, and his wife, Lacey races to save himself from arrest, even it means bringing to light painful scandals from his own past.