Line of Fire (1)

Christmas in Denton, and the body count opens early. A power station worker, Cockcroft, dies in a fall that looks like an accident, days after his house was burgled and his fish tank destroyed. Then a young detective from the regional crime squad, Tim Fox, is murdered — shot dead with £1,000 of cash in his car, which the squad's leaders immediately read as proof of corruption in an organised car-theft gang. Frost, convinced the cash is a planted detail, persuades the Chief Constable to let him back onto the case.

The regional squad is run by Detective Superintendent Larry Finlay and his deputy DI Mark Newcombe, and the closer Frost looks, the more the neat explanation frays. There are no signs of self-defence — the killer knew Fox. And Fox's wife Helen is not what she appears: she tells Frost she ended an affair with Newcombe because he became obsessive and violent, and she thinks he murdered her husband to leave her free. Frost notices Newcombe has a new mountain bike with tyres matching tracks found near Fox's body; Newcombe claims he bought two, gifting one to Helen. The gun that killed Fox is conveniently found during the squad's raid on the car thieves — planted, Frost is certain, to frame the gang.

Alongside the murder, the episode runs two smaller threads: a string of pet shootings with a rifle, and house break-ins where little is taken but much is wrecked — the work of an aggressive, misogynistic power-plant employee named Ray English, who has been warned off Cockcroft's daughter. And in the middle of it all, Frost collides with Shirley Fisher at the hospital, where she asks his help for a sixteen-year-old who has just given birth and plans to run away. The girl's father, confronted, embraces his grandchild and begs forgiveness; Frost and Shirley arrange to meet later — and Frost walks into a bank robbery.

Line of Fire (1), written by Michael Russell and directed by Robert Knights, is the series' Christmas special with a body count — a two-parter that strands its hero mid-robbery and leaves the corruption case wide open. It is the show at its most propulsive, with every thread pointing at a system protecting its own.

A Christmas special that opens with a murder and strands its hero in a bank robbery — pure Frost, and a cliffhanger that made the wait for part two agonising. A Christmas cliffhanger that made the wait agonising.