In nineteenth century Mesopotamia a series of romantic enganglements ensue.

A little girl wakes from a dream about the old armchair in which she has fallen asleep. The dream concerns a hidden letter, a hidden hoard of money and a wrongfully convicted man.

Inspector Hanaud is asked to investigate a murder in which a young woman is accused of killing her wealthy employer in a Riviera mansion and then running away. She is innocent, but the villain is able to make her seem guilty. Hanaud uncovers the truth, that the murder was the result of a jewel robbery gone wrong.

Arsène Lupin, alias the Duke of Charmence, is a clever gentleman burglar. Detective Guerchard has vowed to bring Lupin to justice. Given a chance to escape when caught with the goods, Lupin gives up his freedom for the love of a good woman.