Episode 4

A serial killer continues targeting women who are alone at night. He takes a piece of jewellery from each of them, and gives one of their lockets to his unknowing wife, as a birthday gift. He escalates rapidly, and Luther's team is forced to enlist the help of the killer's wife, in order to track him down. He is successfully taken alive, but his wife assaults him in a fit of rage, striking him with a hammer in the back of the head. In an attempt to win Luther's friendship, Alice impersonates a doctor and lights a fire in the hospital, taking advantage of the distraction to fatally smother Henry Madsen.