Luther must confront a demon from his past, as both the police and Cornelius converge on his home. With Halliday convinced that the body in the morgue isn't their killer, can Luther put his own troubles to one side and find the true murderer before he strikes again?

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?