Episode 3

The pressure comes at Luther from two directions and neither gives. A friend he cares for is suddenly in real peril, and at the same time a young woman has been snatched by the relentless killer. On top of both sits Cornelius's violent revenge, which is threatening to consume everyone in its path. Luther has to choose who to save, and the episode does not pretend there is a right answer. It does not pretend there is an easy one either.

The moral mathematics of the hour are ugly. Every minute spent on one rescue is a minute the other person does not have, and the show keeps the clock running on both. The friend and the young woman are never far apart in the episode's thinking, and that is deliberate. Luther is not built to let people die, which is exactly why the killer and Cornelius have arranged the situation the way they have. They are not attacking his strengths. And they are attacking the thing he cannot switch off.

Neil Cross wrote it, Jamie Payne directed. Idris Elba gives one of the season's most exposed performances, a man running on fumes and refusing to admit it. Ruth Wilson's Alice Morgan hovers with her usual unreadable calm, Patrick Malahide's George Cornelius and Andrew Mullan's Alastair Cornelius make the family menace credible, and Michael Smiley's Benny Silver, Lex Daniel's Ronald Massey, Gary Hailes's Donnie McKinney, Enzo Cilenti's Jeremy Lake, Katie Brayben's Penny Leyton and Hermione Norris's Vivien Lake keep the world properly populated.

The episode is at its best when it stops explaining and just watches Luther tear himself in half. Duty and devotion were never going to sit comfortably in the same man.

It ends with a choice made and the cost still being counted. That is Luther's whole career in one line.