A clock-obsessed killer terrorizes London, leaving a trail of bizarre murders that force Dr. Gideon Fell to intervene. Dr. Gideon Fell, a portly detective with a formidable intellect, seeks to solve the mystery behind the theft of clock hands from a monumental timepiece. He faces a madman who uses these stolen objects as weapons, creating a series of impossible crimes that challenge the logic of Scotland Yard. The narrative follows a traditional investigative framework, focusing on the methodical deduction required to unmask a killer who operates with precise, mechanical cruelty.

Readers and critics frequently highlight the intricate plotting and the clever use of mechanical motifs that define this entry in the Dr. Gideon Fell series. Discussion often centers on the author's ability to construct a seemingly impossible crime that remains grounded in logical, albeit complex, explanations. Many appreciate the atmospheric tension created by the clock-obsessed antagonist, which adds a distinct flavor to the traditional detective format. The pacing is noted for its steady build, allowing the reader to follow the detective's thought process alongside the investigation. Overall, the work is regarded as a quintessential example of the Golden Age style, appealing to those who enjoy cerebral puzzles and classic mystery conventions.