One summer’s day, a man is lured out of his garden for a private conversation. Ms. Teller, the daughter of his mentor, gives him the task of tracking down Modal, a suspect in the eyes of the Non-Crime Unit. The former agent (with a telltale “M” monogrammed on his pajamas) gives himself “the name of a famous detective” and sets out on his local odyssey, leaving his wife and daughter behind.

The agent’s first steps put him in touch with PQ, a disgraced police clerk, CM, an alluring harpsichordist, Dr. VK, a travelling psychiatrist, and Barbie, a surprisingly resourceful realtor. He takes up lodging with an eccentric family in their “complex” and soon finds himself spending time with an actress, a linguist, a transcriber, and a Shakespeare professor, all with something to share about Modal.

Still haunted by a botched operation and the memory of his fellow infiltrator, Esme, the agent persists in using the method detailed in Teller’s procedural guide, Scent of a Non-Crime. Yet his overidentification with Modal is the least of his worries as the anticipated conflict inches dangerously close to home. Scent of a Non-Crime is the third book Morse's acclaimed 'Tulpaverse', proceeded by Tulpa Mea Culpa and Retcon.