Episode 6

Steve Arnott is arrested on suspicion of murder, and he protests his innocence all the way through. It is the kind of reversal the series specialises in: the hunter, suddenly the hunted. Meanwhile Kate Fleming's undercover operation is still running, and the facts it is turning up could settle Steve's guilt or clear it. The same operation may finally name the Caddy, and the episode holds both possibilities open. The unit that usually asks the questions is now answering them, and nobody enjoys the exchange.

The episode holds two investigations in the air at once. On one side, the case against Arnott, built by people who think they have their man. On the other, Fleming's long game, which is about to pay out in ways nobody predicted. The rooms are full of lawyers and officers and people choosing sides, and the weight of it all presses down on Arnott in particular. Fairbank's solicitor hovers at the edges, and Patrick Fairbank himself is part of the story now. Every conversation in the episode feels weighted, and the show does not waste the tension. The interviews are long, and the answers are shorter every time.

Jed Mercurio wrote it, John Strickland directed. Martin Compston gives one of his best performances as a man watching his life get taken apart, and Vicky McClure's Fleming keeps the other half of the story moving. Keeley Hawes's Denton, Craig Parkinson's Cottan, Adrian Dunbar's Hastings, Maya Sondhi's Bindra, George Costigan's Fairbank, Joanne Crawford's solicitor, James Edlin's Lambert and Lucia McAnespie's custody sergeant complete the cast. It is a large cast, but the episode keeps every thread visible.

The question of who to trust has never had more at stake. Arnott's fate and the identity of the Caddy are tangled together, and the episode is not letting either one go cheaply. But the answers, when they come, will not be comfortable ones. The tension is held right to the closing moments, and the show makes you feel the weight of it. That much, at least, is certain.