Gervase Fen, an eccentric Oxford professor, must apply his sharp intellect to solve a series of sixteen perplexing criminal puzzles. Fen operates within the framework of the classic British whodunit, navigating social conventions and logical inconsistencies to identify perpetrators. His primary objective involves untangling complex alibis and physical clues that baffle local authorities. The narrative structure relies on the interplay between Fen's whimsical personality and the rigid, often claustrophobic settings of mid-century English life.

Readers frequently highlight the intellectual playfulness and rapid pacing inherent in these short mysteries. Discussion often centers on the balance between the lighthearted, often humorous tone and the intricate construction of the puzzles themselves. Critics note that the stories serve as a showcase for the author's ability to condense complex clues into brief, satisfying narratives. The character of Gervase Fen remains a focal point for those who appreciate the tradition of the erudite, unconventional detective.