Bloodlines

Susan Keller served a life sentence for murdering her family when she was a teenager, and her release brings howls of protest. When members of her family start dying one by one soon after, the obvious reading is that someone is taking revenge. The team's job is to work out who, before the pattern finishes its work. The protests at the gate are part of the story, because the public verdict on Keller was settled long before the courts got involved. The deaths come with a horrible regularity, the kind that gives a detective nightmares.

Keller accepts an offer of a country retreat, and because the whole thing smells like a trap, the Taggart team is assigned as protection. That puts the police in the odd position of guarding a woman most people would happily see back inside. The retreat is the kind of mercy that looks like a cage from the outside. The protection detail is the episode's quiet engine, the thing that keeps the family drama from drifting.

But the question the episode keeps open is whether the killer is Keller's anonymous benefactor or someone much closer to home. It is a neat family-mystery frame, built around a small set of relatives and a long history. The victim may be the most dangerous person in the room. The family is small enough to hold in one hand, which makes the body count feel personal.

Glenn Chandler wrote it, Alan Macmillan directed. James MacPherson, Blythe Duff, John Michie and Colin McCredie lead, with Robert Robertson as Dr Andrews. Aline Mowat's Susan Keller, Anne Kidd's Helen Duncan, Lindy Whiteford's Eleanor McNair, Tom Cotcher's Peter McNair and Heather Ann Foster's Alice Buchanan complete the cast.

Revenge plots this old-fashioned can go flat fast. This one keeps its nerve, mostly because Mowat's Keller is allowed to be more than a figure of pity. It is a revenge story told at walking pace, and it is better for it.