Episode 4

Jo Davidson faces increasing pressure from all sides. AC-12 makes major breakthroughs in the investigation, and the case against the people circling Vella's murder starts to take shape. But an attempt to interview a key witness goes horribly wrong, and the setback lands at the worst possible moment. Professional confidence does not survive contact with that kind of failure. The witness was supposed to be the moment the case turned, and instead it turned on the team. The pressure on Jo is coming from every direction at once, and the episode tracks each front.

The episode runs on the gap between progress and disaster. The breakthroughs are real. But they are fragile, and the botched interview demonstrates exactly how fragile. The team has to absorb the failure and keep moving, and the show is good at showing that process in all its unglamorous detail. Jo's position grows more exposed by the hour, and the walls around her keep getting thinner. The show has always been honest about the unglamorous parts of an investigation, and this is one of them.

Jed Mercurio wrote it, Gareth Bryn directed. Kelly Macdonald's Jo is under siege, and the pressure is written all over the episode. Vicky McClure's Fleming, Martin Compston's Arnott, Adrian Dunbar's Hastings, Perry Fitzpatrick's Lomax, Gregory Piper's Pilkington, Nigel Boyle's Buckells, Shalom Brune-Franklin's Bishop, Elizabeth Rider's Wise and Ace Bhatti's Sindwhani complete the cast. It is a dependable cast, and the episode leans on it heavily this week.

The truth in this world rarely arrives neatly packaged. It leaks out through incompetence, exhaustion and bad luck, and the episode is a demonstration of that principle. The investigation is closer than ever, and the failure makes the nearness hurt more. But there is a special kind of tension in watching people nearly get it right. The near-miss is worse than the miss, and the episode knows the difference. The breakthrough and the disaster are the same coin, and the coin keeps flipping.