When the reclusive laird of Erchany plunges to his death from his own castle ramparts, Inspector Appleby must determine if the event was a tragic accident or a calculated homicide. Appleby navigates the isolated, atmospheric landscape of the Scottish Highlands to uncover the truth behind Ranald Guthrie’s demise. He faces a web of local superstition, family secrets, and the psychological instability of those residing within the castle walls. The narrative employs a traditional investigative framework, focusing on the methodical deconstruction of alibis and the examination of the victim's complex personal history.

Readers frequently highlight the dense, literary prose style that distinguishes this work from standard golden age detective fiction. Discussion often centers on the effective use of the bleak Scottish environment to heighten the sense of isolation and impending doom. Critics often note the balance between the intricate puzzle-solving of the mystery and the deeper exploration of the victim's troubled psyche. Many readers appreciate the intellectual rigor Appleby brings to the investigation, though some find the pacing deliberate and reflective rather than action-oriented. The book is widely regarded as a significant entry in the genre for its stylistic ambition and atmospheric depth.