Sir John Appleby finds himself at the center of a lethal investigation when an archivist falls to his death from the heights of a remote castle. Appleby must navigate the eccentricities of the Ampersand estate to determine if the death of Dr. Sutch was a tragic accident or a calculated homicide. He faces a cast of suspicious inhabitants who prioritize the recovery of hidden papers or gold over the truth of the incident. The narrative employs a traditional third-person perspective, emphasizing logical deduction and the unraveling of complex social dynamics within the isolated setting of Treskinnick Castle.

Readers frequently highlight the witty and erudite prose style that characterizes the work of Michael Innes. Discussion often centers on the intricate plotting and the author's ability to balance humor with the gravity of a murder investigation. Critics often point to the atmospheric setting of the castle as a primary driver of the narrative tension. Many readers appreciate the intellectual challenge presented by the puzzle-like nature of the mystery. The book is widely regarded as a representative example of the golden age style of detective fiction.