An erudite amateur detective investigates a string of cryptic murders tied to nursery-rhyme clues and a killer using the alias Bishop. The inquiry proceeds through forensic work, interviews with scientists, mathematicians, and acquaintances, and a sequence of puzzles involving ciphered notes, archery, chess, and mathematical formulas. As the detective pieces together motive and method, the case intensifies with new victims, a stolen weapon, and tense nocturnal encounters. The plot interweaves methodical deduction with mounting suspense, concluding with a logical denouement that explains how the symbolic clues point to the perpetrator and the reasons behind the killings.