Episode 4

Tensions rise inside the OCG in the wake of the events at Eastfield, and the question hanging over everything is the identity of H. The mystery has been running for a while now, and this episode lets it work on everyone. Inside AC-12, suspicions are mounting too, and the team is starting to look at each other differently. The word H has become a weight that everyone carries. Nobody at AC-12 is above suspicion anymore, and the episode makes that plain.

The episode is about the corrosive effect of an unanswered question. But the officers cannot work without wondering who among them is compromised, and the OCG cannot operate without wondering who is feeding information out. The result is a thick, unpleasant atmosphere that the show manages beautifully. Familiar faces start to look less familiar, and the doubt spreads in every direction. The cracks in the department are showing, and the fall of Eastfield is still sending ripples through the organisation. It is a quiet episode in some ways, but the quiet is the point.

Jed Mercurio wrote it, John Strickland directed. Adrian Dunbar's Hastings carries the weight of the episode, with Martin Compston's Arnott and Vicky McClure's Fleming circling the question of H. Aiysha Hart's Railston, Andrea Irvine's Roisin, Stephen Graham's Corbett, Rochenda Sandall's McQueen, Rosa Escoda's Yao, Taj Atwal's Sohota and Polly Walker's Biggaloe complete the cast. It is a large cast, and the episode lets the suspicion play across all of it.

The episode keeps the viewer guessing about H while making it clear that the guessing is the point. Everyone has a secret, and the show is in no hurry to sort them out. The stakes feel high, and they are. But the answers, when they come, will cost the people who find them. The hunt for H is now the hunt for a name, and the name is getting closer to home. The team is being watched as closely as it is watching, and the watchers are inside the building.