Episode 2

After the shooting at the drugs house, Kate Fleming uses her undercover role to keep the pressure on Danny Waldron's unit. She feeds the investigation from the inside while the armed response team tries to work out who is watching them. Meanwhile, a previous AC-12 investigation comes under legal scrutiny, and Steve Arnott makes a shocking discovery. His own past catches up with him before the hour is out, and the two strands of the episode pull at each other all the way through. It is a double-edged week for the team, and the episode plays both edges.

The episode puts everyone in a compromising position and leaves them there. Fleming has to play a role while her real colleagues pull strings from outside. Arnott finds that the past does not stay filed away, especially when the present is this complicated. The unit under scrutiny finds its methods questioned at every turn, and the mistrust spreads sideways through the ranks. Nobody is getting out of this week with clean hands, and the show does not pretend otherwise.

Jed Mercurio wrote it, Michael Keillor directed. Vicky McClure and Martin Compston carry the week, with Daniel Mays's Waldron holding the line under pressure. Lisa Palfrey's McAndrew, Arsher Ali's Bains, Leanne Best's Brickford, Will Mellor's Kennedy, Shaun Parkes's Reynolds, Polly Lloyd's paramedic and Michael Donald's doctor fill out the supporting cast. The ensemble is one of the show's best, and the episode knows how to share the work.

The ghosts of past actions do not stay quiet for long in this world, and the episode proves it twice over. The legal scrutiny of the earlier inquiry is a reminder that AC-12's own methods can be put on the stand. But it is a grimly efficient hour of television. The discovery at the heart of the hour will not stay contained, and the show is already building towards the fallout. The past is coming for everybody, and it is not bringing good news.