Walter Longcluse is clever, cunning and rich. Having insinuated himself into the affections of the Arden family, he becomes devoted to the beautiful young Alice, although she cannot bring herself to like this strange and mysterious friend of her brother's. Then Longcluse visits a gambling club with Alice's brother, Richard, and finds himself confronting the indiscreet Monsieur Lebas, with whom he had been mixed up in the past. Later the same evening Lebas is found stabbed. What is the secret of Longcluse's disfigurement and the 'dark' past which he reveals to no one? Why did Mrs Tansey, the Ardens' housekeeper, react so strongly when she recognized Longcluse's voice? What is it that Longcluse so fears?