A series of seemingly random murders in London forces an actor who specializes in playing Sherlock Holmes to apply the detective's methods to real-world crime. Sheridan Haynes, an actor currently portraying the famous detective on stage, finds himself entangled in a genuine investigation when the police struggle to connect a string of violent incidents. He must navigate the skepticism of law enforcement while utilizing his deep knowledge of Arthur Conan Doyle's canon to interpret clues that others overlook. The narrative follows a traditional mystery structure, blending the theatricality of the stage with the gritty reality of 1970s London crime. Haynes faces the logical constraint of lacking official authority, forcing him to rely on observation and deduction to survive the escalating danger.

Discussion often centers on how Julian Symons balances the homage to the original Holmes stories with a modern, cynical crime setting. Readers frequently highlight the cleverness of the protagonist's dual identity as both an actor and a detective. Critics often note the precise, understated prose that avoids melodrama while maintaining a steady sense of suspense. The book is frequently cited for its intellectual approach to the mystery genre, appealing to those who enjoy puzzles that require careful attention to detail. Many readers appreciate the way the narrative deconstructs the myth of the detective while simultaneously celebrating the mechanics of the classic whodunit.