A gruesome serial killer terrorizing London while the brilliant but disgraced detective John Luther sits behind bars. Haunted by his failure to capture the cyber psychopath who now taunts him, Luther decides to break out of prison to finish the job by any means necessary.

With Luther's increasing absence from the case, Halliday leads the hunt for a monster on the loose - a killer determined to complete his final macabre masterpiece...

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

The police and Cornelius converge on Luther's 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 they strike again?

A new spate of nightmarish murders brings DCI John Luther to once again face the depths of human depravity on the streets of London. While the monstrous and seemingly indiscriminate killings become ever more audacious and public, Luther and new recruit D.S. Catherine Halliday are confounded by a complex tangle of leads and misdirection that seems designed to protect an untouchable corruption. As the body count rises, and gangster George Cornelius applies his own pressure, can Luther catch a killer and save his own neck?