Knife

Most fugitives are dangerous to the public in the abstract. Debbie Richard is dangerous to Maggie in particular. The teenager has escaped from a top-security remand centre, and on top of hating men in general and her parents in particular, she has sworn to kill Maggie on sight. That makes the hunt personal in a way police work rarely is. It's one thing to chase a fugitive, and quite another to chase one who has your name on a list.

And the hunt is the episode. Maggie has to find a girl who knows she's wanted and doesn't care, a girl with nothing left to lose and a grudge with Maggie's name on it. The chase takes her through the edges of the city, from the Burwells to the Richards, every stop a possible sighting, every answer a dead end. Every tip has to be checked and every sighting chased, and the tension lives in the running count of hours since the escape. Sylvestra Le Touzel plays Debbie with a coiled anger that makes the threat feel real, and you understand why Maggie keeps going back to the obvious places even when they turn up empty.

Ray Jenkins and Terence Feely wrote it, Christopher Baker directed. Jill Gascoine is Maggie Forbes, with William Marlowe's Russell, Derek Thompson's Fenton, Brian Gwaspari's Croft and Paul Moriarty's Barratt running the hunt alongside her. Neil McCarthy plays Ralph Burwell, Mary Healey is Mu Richard, Anthony Langdon plays Jack Richard and Nigel Rathbone is Steve Forbes.

It's a taut hour about professional boundaries under pressure, and the best scene work comes from the quiet moments between the running. Maggie never once stops being a detective, but you can see the mother in her too, and the episode doesn't need to spell out why that matters. The title is blunt, and the episode earns it: this is a story about what a knife in the wrong hands does to everyone within reach.