In 1930s London, celebrity psychiatrist Anselm Rees is discovered dead in his locked study, and there seems to be no way that a killer could have escaped unseen. There are no clues, no witnesses, and no evidence of the murder weapon. Stumped by the confounding scene, the Scotland Yard detective on the case calls on retired stage magician-turned-part-time sleuth Joseph Spector. For who better to make sense of the impossible than one who traffics in illusions?