A new spate of nightmarish murders brings DCI John Luther to once again face the depths of human depravity on the streets of London. As the body count rises, and gangster George Cornelius applies his own pressure, can Luther catch the killer and save his own neck?

With his friend in peril and a young woman kidnapped by the relentless serial killer, can Luther protect the innocent while preventing Cornelius's violent revenge from consuming him? Who is Luther willing to save, and who can't he bear to lose?