Thorne: Sleepyhead

Three women are found murdered, their killer having caused his victims to have strokes. A fourth victim is still alive and might be able to identify her assailant but she cannot communicate as she has been left with locked-in syndrome. Investigating, DI Tom Thorne concludes that it was the killer's intention to leave his victims incapacitated, not dead.

Thorne is forced to conduct his investigation alone when Tughan (Eddie Marsan) dismisses his "locked-in" theory. He and Anne Coburn (Natascha McElhone) try to help victim Alison Willetts communicate. A woman who claims to have escaped the killer is attacked.

Tughan (Eddie Marsan) identifies pathologist Phil Hendricks (Aiden Gillen) as his prime suspect and seems determined to expose the dark secret that binds him to Thorne. Anne's daughter, Rachel, unwittingly puts herself in danger.