DCI Luther must outmanoeuvre a trained sniper on a mission to kill police officers. But as the body count rises and the killer's true motives are revealed, Luther puts himself in the line of fire to try and draw the killer into the open. Meanwhile, Alice Morgan has been investigating Luther's past - and is threatening to tell Zoe what she has discovered.

When a serial killer goes on the rampage, Luther must put his personal life aside and delve inside the murderer's mind to discover what is driving him to kill so many girls, and why. Meanwhile, serial killer Henry Madsen wakes up from his coma, and Alice takes matters into her own hands when Luther cuts off contact with her.