Close Encounters

Frost is reunited with DS Hazel Wallace — now a detective sergeant and a mother, having left a baby in his office as her announcement — for two cases that could not be more different. The first is a string of robberies at newly-bought houses, each hit coming just after a removal job. Frost, following the pattern, lands on a removals man with money problems who has been tipping off burglars. The case detours through a divorced couple's missing seven-year-old — the boy is found hiding in his father's workplace, having run away in the vain hope that the search for him would reunite his parents — and ends in a high-speed chase of the gang's scout, pursued by a fleet of delivery riders from Frost's favourite takeaways joints.

The second case is stranger. A security guard is murdered at Lightfoot quarry, and the only witness is Laurence Burrell, a young autistic man played by Jim Sturgess in an early career turn — a man convinced aliens and the American government are pursuing him. Forensic evidence ties Burrell to the murder weapon; he is taken in, but trapped in an unfamiliar place he cannot cope: he absconds, steals explosives from the quarry, and rigs the site to blow, intending to destroy it so the aliens will leave him alone.

Underneath the tragedy is a businessman's war. the quarry's owner, Charlie Lightfoot, accuses his old partner Stuart Mackintosh of the killing — Mackintosh needs the quarry as a lake for his housing development, and Lightfoot, ruined by Mackintosh decades earlier, is selling it only at a punitive price. Frost, left incapacitated after the explosives are found, watches Burrell calm himself and carry him to safety before the blast. Mackintosh, with investors ready, has Lightfoot killed — but Burrell's testimony unravels him, and Frost arrests the developer and his henchman.

Close Encounters, written by Michael Russell and directed by Paul Harrison, is a gentle, generous episode — Wallace's motherhood, the runaway boy, Burrell's strange dignity — wrapped around a very ordinary story of greed. Sturgess, all tics and terror, gives the episode its heart; Frost's decision to trust him is the series' faith in human nature, undimmed after ten years.

A gentle, generous hour about trust — Frost trusting an autistic witness, a runaway boy trusting a reunion that never comes, and Hazel Wallace starting a family of her own. A gentle hour about trust and strange dignity.