Chief Inspector John Luther returns to work again after isolating people to investigate a more mysterious criminal incident in a fourth season filled with surprise,While on a leave of absence, Luther is suddenly dragged back into his former life in London to battle the demons of his past and to stop a cannibal serial killer.Will a cold case unlock the mystery from Luther's past that is haunting him? The detective is forced to put himself and Emma in danger to stop the serial killer's end game.
