“Thorne Sleepyhead” centers on Detective Inspector Tom Thorne as he delves into the case of a perplexing serial killer. The first three victims met their demise, but the fourth, Alison Willetts, was less fortunate. She survived a stroke that was intentionally triggered by the killer’s precise manipulation of pressure points on her head and neck. Although Alison is conscious and can perceive her surroundings, she is trapped in a state where she cannot move or communicate. The authorities suspect that by leaving Alison alive, the killer may have committed his first error.