Episode 2

Episode two is a detective hour at heart, and the show wears the change well. The unit's job has turned into the dull, grinding kind: connecting victims from separate incidents and finding out what ties them together, when the files on their own lead nowhere. The team works the case like a jigsaw missing its box lid. And then a well-meaning intervention goes wrong, and the whole unit ends up more lost than it was before. Nobody is satisfied with that, least of all Lana.

Chris Brandon and Daniel Brierley's script treats each case file like a piece of a larger puzzle, and the slow work of assembly is the episode's engine. Director Jamie Donoughue lets the process breathe: the interviews, the cross-checks, the paperwork, the small silences where someone tries to work out who to trust. There is real tension in watching methodical police work, and the well-meaning intervention, when it finally comes, lands like a stone in a still pond, sending everything they thought they knew scattering.

The cast carries it well. Vicky McClure's Lana and Kevin Eldon's Jeff are the episode's heart, and the script gives them a quiet, repeated argument about where helping stops and meddling begins. Nabil Elouahabi's Hassan Rahim, Jason Flemyng's Steven Wyles, Tom Glenister's DC Neil Brenton, Kerry Godliman's Sonya Reeves, Michael Gould's Ned Cole, Tamzin Griffin's Val, Christopher Hatherall's Phil Croxley and Simon Kunz's Ewan Knox all feed the growing confusion.

It is a tense hour, and an unusually patient one for a show that usually likes things to go off. The lesson is delivered without a sermon: good intentions are no substitute for knowing what you are doing. By the end the unit looks less like a team of experts and more like a room of people discovering how much they do not know. For a series built on big bangs, that is a brave way to spend an hour.