Episode 7

Lucas North's past keeps reaching for him, and Vaughan Edwards keeps pulling the strings. This week it is the Albany file, whatever it holds, and Vaughan has decided to raise the stakes until somebody has to break. Albany has been the ghost in this season's machine, and now it is out in the open. The silent war between the two of them has been running all season, and here it comes to a head.

Most of the episode belongs to Ruth Evershed, which is always welcome. A council worker with too much time and not enough sense has convinced himself he has found a dead drop in a local park, and he will not leave it alone. Ruth keeps her distance at first. Then curiosity gets the better of her, and she walks into a situation that neither she nor the man who dragged her there could have seen coming. The business with the dead drop is played for genuine unease rather than comedy, which is the right call. Nicola Walker handles the whole thing with Ruth's usual blend of competence and quiet alarm, and the episode is better for giving her the centre of the stage.

Meanwhile Harry and Lucas come face to face, both chasing the same truth about a past they share and neither fully trusts. Anthony Neilson wrote it, Edward Hall directed. Peter Firth and Richard Armitage do the heavy lifting, with Nicola Walker's Ruth at the heart of the story and Shazad Latif's Tariq, Sophia Myles's Beth, Max Brown's Dimitri, Iain Glen's Vaughan, Laila Rouass's Maya, Hugh Simon's Malcolm Wynn-Jones and Trevor Cooper's Deery in support.

It is a slow-burn episode, more about pressure than action, and the pressure does most of the work. Nobody gets to be a hero here, which is rather the point. And the quiet menace of a nosy civilian finding the one thing he should not have might be the most chilling thing in it.