Episode 5

DCI Roz Huntley is struggling to allay her husband's suspicions, and it is not going well. Nick has started to see the cracks, and Roz cannot keep every door closed. At the same time ACC Derek Hilton bars AC-12 from investigating her, and the unit's future suddenly hangs in the balance. The team has to find a new angle to pursue the case, or watch it die. Every day the bar holds is a day the case gets colder, and Roz knows it.

The episode runs on two kinds of pressure: the domestic kind, where a marriage is quietly disintegrating, and the institutional kind, where a unit's authority is being pulled out from under it. But Arnott, Hastings and the rest are left scrambling for a route around the bar, and the show enjoys watching professionals improvise. Roz, meanwhile, has to hold her household together while the walls close in from outside. The two fronts of the war are being fought in different rooms, but they are the same war. It is the kind of episode that earns its domestic scenes, because the domestic is where the case actually lives.

Jed Mercurio wrote it, John Strickland directed. Thandiwe Newton keeps Roz's composure looking expensive, and Paul Higgins's Hilton makes a coldly plausible antagonist. Adrian Dunbar's Hastings, Martin Compston's Arnott, Vicky McClure's Fleming, Claudia Jessie's Taylor, Mark Stobbart's Twyler, Anneika Rose's Jatri, Nigel Boyle's Buckells, Maya Sondhi's Bindra and Syreeta Kumar's trauma consultant complete the cast. It is a strong ensemble, and the episode shares the weight fairly.

The episode is a reminder that the investigation's biggest enemy is often the institution itself. Hilton's intervention is not drama for its own sake; it is the kind of power play the series has always understood. AC-12 has been blocked before. But the interest is in watching it find the way around, and this time the clock is shorter. The unit's future hangs on the next move, and the next move is not obvious to anyone.