The sudden death of a wealthy tycoon triggers a high-stakes identity theft that draws the attention of a seasoned investigator. Arthur Povey assumes the life and fortune of his deceased brother, Charles, following a fatal boating accident, hoping to secure a life of luxury. His deception faces immediate pressure when a former mistress of the deceased identifies the imposter and initiates a blackmail scheme. The narrative follows the ensuing power struggle as Sir John Appleby enters the scene to untangle the web of deceit and uncover the truth behind the accident.

Readers frequently highlight the clever premise of the identity swap as a standout element of the narrative. Discussion often centers on the dry wit and intellectual rigor that Sir John Appleby brings to his investigations. Critics often note the author's ability to maintain suspense through intricate plotting rather than relying on overt violence. The balance between the protagonist's internal calculations and the external pressure of the blackmail plot creates a steady, engaging rhythm for the reader. Many fans of the genre appreciate the sophisticated tone and the focus on the moral ambiguity of the characters involved.