Retired police officer Luke Fitzwilliam encounters an elderly woman named Miss Pinkerton on a train, who claims that a serial killer is at work in her village. When she later dies under suspicious circumstances, Fitzwilliam heads to the village of Wychwood-under-Ashe to investigate. As he delves into the seemingly tranquil community, he uncovers a series of mysterious deaths that appear to be anything but accidental. With each new clue, Fitzwilliam finds himself drawn deeper into a web of intrigue and danger, where identifying the killer becomes a race against time.​