When a prominent government minister dies unexpectedly during a routine surgery, Inspector Roderick Alleyn must determine if the cause was medical error or calculated homicide. The narrative follows Alleyn as he navigates the sterile, high-stakes environment of a private nursing home, where every staff member and visitor possesses a potential motive. The investigation is complicated by the victim's political standing and the intricate web of personal relationships among the medical personnel. Told through a traditional third-person perspective, the story emphasizes the methodical gathering of evidence and the psychological interrogation of suspects within a confined setting.

This work is widely regarded as a quintessential example of the Golden Age detective novel, showcasing the author's ability to blend technical detail with classic mystery tropes. Readers often highlight the sharp, witty dialogue and the meticulous construction of the puzzle as the primary strengths of the narrative. The character of Roderick Alleyn is frequently praised for his understated intelligence and polite, yet piercing, investigative style. The novel remains a staple for enthusiasts of traditional British crime fiction who appreciate a well-plotted mystery that relies on logic and observation rather than visceral action.