Episode 6

Nick Huntley faces lengthy questioning as AC-12 pushes for a conclusion. The unit remains convinced Roz is involved, and the finale is a duel: the team against Roz, with Tim Ifield's murderer and the identity of Balaclava Man on the line. Nobody in the episode gets to sit this one out. The stakes have been building all season, and the hour carries all of it. Balaclava Man has been a presence since the start, and this is the episode that finally has to deal with him.

The episode is about how a case closes, and it is not a gentle process. The questioning of Nick is drawn out and punishing. But the show lets the length of it do the work. Roz, meanwhile, has to keep her footing while the evidence closes around her. Every interview is a test, and the answers come at the cost of small surrenders. The show has never been afraid of long scenes, and this episode trusts them completely. Every answer Nick gives is checked against the next, and the room is full of small defeats. The conclusion, when it comes, lands with the weight of the whole series behind it.

Jed Mercurio wrote it, John Strickland directed. Thandiwe Newton and Lee Ingleby carry the final stretch, with Vicky McClure's Fleming, Martin Compston's Arnott and Adrian Dunbar's Hastings driving the case home. India Amarteifio's Sophie, Kwame Che Kandekore's Ollie, Mark Stobbart's Twyler, Anneika Rose's Jatri and Aiysha Hart's Railston complete the cast. It is a cast that has been through a lot together by now, and it shows in the easy weight of the scenes.

There is something satisfying about a finale that trusts its audience to remember six episodes' worth of detail. The duel between AC-12 and Roz is not about who shouts loudest. It is about who has been telling the truth, and the show has been careful about that all season. The answers are here, but they are not cheap. The finale does not cheat the audience, which is rarer than it should be. It pays off what it set up, and the pay-off is worth the wait.