A series of calculated murders orchestrated by an unseen puppet master forces Ellery Queen to identify the true architect behind a simple-minded killer. Ellery Queen investigates a string of homicides committed by Walt, a handyman whose limited intellect makes him a pawn in a larger, lethal game. The narrative follows Queen as he attempts to trace the source of the instructions guiding Walt's actions. The story operates within the constraints of a classic whodunit, focusing on the logical deconstruction of a crime where the primary antagonist remains obscured by the physical perpetrator. The framework relies on the traditional detective procedural style, emphasizing deduction and the systematic elimination of suspects.

Discussion often centers on the unusual production history of this novel, which involved a collaboration between Fred Dannay, Manfred Lee, and science-fiction writer Theodore Sturgeon. Readers frequently highlight the effectiveness of the inverted mystery format, noting that the tension shifts from identifying the killer to uncovering the motive and identity of the manipulator. Critics often observe that the prose reflects a distinct departure from the standard Ellery Queen style due to the heavy involvement of a ghostwriter. The book is frequently cited as a curiosity for collectors and fans of the series who appreciate the technical evolution of the detective genre. Many readers find the dynamic between the puppet and the puppeteer to be the most compelling element of the narrative structure.