PC Joe Penhale's ex-wife Maggie shows up unexpectedly, and appears to have completely forgotten that they split up a couple of years ago.
Bert Large's restaurant is in financial trouble, and he is being chased by loan sharks Alastair Tonken and his son.
Luther's affection for Jenny grows, as does his resolve to protect and help her. He is called in to investigate a man whose brutal and escalating murders seem to have no motive, and leaves Jenny alone and vulnerable.
Luther must rescue Ripley, who has been abducted by Cameron, in time to stop Cameron's final murderous plot. However, Jenny's ruthless and vengeful boss is demanding compensation and Luther is torn.
Luther's 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 is a killer at large whose actions are ruled by his dice.