Straw Dog (1)

At last, a Grace Foley episode. Thirty years ago, at the start of her career, she helped put Tony Greene away for the murder of young men. Now he's appealing, she's asked to give evidence at the hearing, and the whole apparatus of her professional life gets dragged back to its foundation stones. It's the best use the show has found yet for Sue Johnston.

The pressure on her doesn't come only from the courtroom. A copycat killer surfaces, and their game seems designed to force Grace into recanting what she stood by all those years ago. Somebody out there wants her testimony undone, and they're willing to murder in the present tense to manage it. The episode turns memory itself into contested ground: what she remembers of 1980-something, what the institutions remember, and whether either record can survive someone determined to rewrite it.

It's gripping television because it finally points the show's forensic gaze at one of its own. Watching Emma Lowndes play the young Grace in flashback while Sue Johnston holds the present together gives the hour a doubled centre, and the gap between the two women is where all the doubt lives. Did she get it right the first time? She thinks so. Thinking so has kept her upright for thirty years.

Declan Croghan and Barbara Machin wrote it, Jim O'Hanlon directed, first shown in October 2005. Trevor Eve leads as Det Supt Peter Boyd, with Wil Johnson as DI Spencer Jordan, Esther Hall as Dr Felix Gibson and Félicité Du Jeu as DC Stella Goodman around Johnston's Grace. Tom Ellis plays Harry Taylor, Paul Freeman Dr Charles Hoyle, Natalie J. Robb is Emma Lloyd, David Norman appears as Tony Greene in 1980, and Lowndes as Young Grace Foley.

An old case coming home to roost is well-worn territory, but giving it to Grace makes it new. The calmest person in the building has finally been rattled, and that's scarier than any body.