Nothing to Hide

A young homeless drug addict is found dead in a public toilet, and the initial verdict is that Ben Cornish choked on his own vomit. Frost, who distrusts easy answers, presses for the full autopsy and gets a different story: Cornish was beaten to within an inch of his life before he died. The investigation that follows is a tour of the dead man's miseries.

Cornish had a gift for making enemies. He stole from his sister Anne and her husband, Ray; he blackmailed a doctor who had abused him as a child; he was vowing retribution after being thrown out of a squat. Ray Butler finally admits that he intended only to scare Cornish, but the beating went too far. The case resolves almost by accident, a portrait of a life that kept colliding with the wrong people until one of them killed him.

Frost works the case alongside DC Frank Costello, played by Neil Dudgeon in the role that would later make him a star of Midsomer Murders. Costello was shipped down to Denton after decking a superior who had stolen a long-investigated case of his for the glory — a man who has already been punished for the very rule-bending Frost practises daily. The two detectives circle each other warily, and the episode's quietest thread is Frost's encounter with Eileen Grant, a former affair partner he has come to apologise to for ending things abruptly; she has moved on, and the scene — two middle-aged people being honest about old pain — is one of the series' best.

Nothing to Hide, written by Richard Harris and directed by John Glenister, is a deliberately downbeat episode. The title is a cruel irony: everyone in it is hiding something, from the doctor hiding his abuse to the sister hiding her shame. Frost, who hides behind his raincoat and his wisecracks, is the only one who keeps walking into the light.

A quiet hour in a loud series, and all the better for it. Neil Dudgeon's Costello would never return, but his brief partnership with Frost shows how the show could work with two broken men at its centre. A low-key hour that rewards patience, and the debut of a fine actor.