Luther's personal and professional life spirals out of control as he tries to cover up Toby's death and appease a suspicious Baba. He must also protect Jenny from any further harm. At work there's also a killer at large whose actions are ruled by his dice. How do you stop a man who sees life and death as a game and whose actions can't be predicted?

As Luther's affection for Jenny grows, so does his determination to protect her and help her back on her feet. Baba, however, is determined to keep Luther on a tight leash. To add to Luther's difficulties, he is called in to investigate a man whose brutal and escalating murders seem to have no motive, leaving Jenny alone and vulnerable.

Still plagued by the death of his ex-wife, Luther returns to work to face a surreal and nightmarish case of a masked murderer determined to enter into folklore. As the body count rises, Luther must use all his skills to stop the killer, at the same time trying to rescue an old acquaintance's daughter from the dangerous world of prostitution.

Luther must rescue Ripley, abducted by Cameron, in time to prevent Cameron's final murderous set piece. But Jenny's ruthless and vengeful boss is demanding compensation for stealing her protege. Luther is torn; will his visionary mind provide the team with the tools to save Ripley and the killer's intended victims, or will his focus be compromised?