Missing Persons (1)

It starts with something small and horribly ordinary: a woman steps in to protect her daughter from a mugger, and from that one act of courage her whole family slides into mortal danger. That is the opening move of Missing Persons (1), the first half of the story that opens Waking the Dead's seventh series.

From a street mugging the case widens out in directions you don't expect. The key to the cold case, it turns out, lies with three very different figures from Europe's violent recent past: a Basque terrorist, an Algerian revolutionary and a ruthless IRA agent. It is an ambitious sprawl for two hours of television, and part one mostly spends its time laying the ground, introducing the players and letting the ordinary dread build. The show has always been good at that slow tightening, where a family's quiet life turns out to have history coiled underneath it. Here the history is political, which makes a change from the usual bones-in-the-garden business, and gives Grace Foley and the team rather more to argue about over the whiteboards.

Declan Croghan and Barbara Machin wrote it, Tim Fywell directed. The core unit is intact: Trevor Eve as DSI Peter Boyd, Sue Johnston as Dr Grace Foley, Tara Fitzgerald as Dr Eve Lockhart, Wil Johnson as DI Spencer Jordan and Félicité Du Jeu as DC Stella Goodman. Around them sits a strong guest cast: Michelle Forbes as Sarah, Beatriz Batarda as Lore Carson, Justine Mitchell as Una Doyle, Marina Koem as Fatima Yacif and Daniel Cerqueira as Brahim Haddou.

Part one of a two-parter has one job, really: make you come back tomorrow night. This one manages it by refusing to explain itself too quickly. Threads are dangled, loyalties stay murky, and the sense that Sarah and her children are in genuine trouble never quite lets up. If there is a complaint, it is that the geopolitical plotting asks you to keep a lot of names in your head at once. But the show earns its complexity by keeping the human stakes simple and sharp: a mother did the brave thing, and now everyone she loves may pay for it.