A wager involving a penniless trek from South Africa to London concludes with the discovery of a corpse in a hotel room, thrusting an innocent man into a complex murder investigation. Christopher Kent, attempting to complete a bet that requires him to travel without using his own funds, finds his situation compromised when he encounters a dead woman in a room he entered under false pretenses. He must navigate the scrutiny of law enforcement and the intricacies of the crime scene to clear his name. The narrative utilizes a third-person perspective to track the movements of the protagonist and the subsequent investigation led by Dr. Gideon Fell, focusing on the logical deconstruction of a seemingly impossible crime.

Readers frequently highlight the technical proficiency of the plot, noting that the author excels at constructing complex puzzles that demand close attention to detail. Discussion often centers on the effectiveness of the locked-room scenario, which serves as a hallmark of the author's style during the Golden Age of detective fiction. Critics often point to the balance between the lighthearted premise of the bet and the grim reality of the murder, which creates a distinct tonal contrast. The pacing is generally described as methodical, favoring logical deduction over high-octane action sequences. Many enthusiasts of the genre appreciate the intellectual rigor required to solve the mystery alongside the protagonist.