Duncan Greive: Real life murder tale makes for compulsive viewing

Hazel Buchanan (played by Genevieve O'Reilly) and Colin Howell (played by James Nesbitt) in The Secret.

The Secret, based on a bizarre true story, is both painstakingly paced and a show in a hurry. The first episode rattles through a lengthy affair from spark to inflammatory conclusion so breathlessly you barely have a chance to absorb its implications. The second spends nearly its entire span on a single night.

Shockingly, its four episodes cover 20 years, so the pace is likely to lurch again as it winds toward a conclusion. The events it cover take place in Coleraine, Northern Ireland, commencing in the early '90s. The town was then part of the Troubles, visited by death and bombings, yet we open on a pretty vision of small town life, good-hearted people going about their business.

The town's dentist is Colin Howell, played by a menacingly impassive James Nesbitt. He develops a fixation on Hazel Buchanan, the wife of a fellow-Baptist church goer, and initiates physical intimacy in a skin-crawling scene at a public pool.

The pair commence a whirlwind affair, with Howell running through the night before appearing sweat-soaked and shaking at her kitchen window, while her police officer husband is out on patrol. Between the incident and the pool and his appearing unbiden at her garden by night it's clear we're dealing with, bare minimum, a dangerous and criminal stalker. But Buchanan, far from being repulsed, falls for his routine. The God so present in the families' lives, far from being an impediment, becomes an enabler - an entity who would not have brought them together without intending to. Within their addled minds, it's a short step to imagining a world without their spouses in it.

We follow Nesbitt's Howell for the vast majority of the show, which is predominantly shot with hand-held camera, a rarity in prestige drama. The intimacy it grants makes the idle domesticity of its early moments feel like a well-produced home movie. When Howell starts to turn that same closeness gives us an eerie proximity to his mental disintegration.

We're on his shoulder as he goes to work, we look into the mouths of his patients and see the mask he presents to the world - that calm, resolute bedside manner near-unique to the dental profession - disintegrating in private. When their affair, conducted with minimal attempts to hide it, is inevitably discovered, the Church attempts a shabby band-aid solution. Howell does a bit of vacuuming and tries to avoid eye contact. Within what feels like a few weeks everything appears normal. Soon it starts up again.

Hazel Buchanan, played by Genevieve O'Reilly in a scene from the TV show, The Secret.

The wronged spouses are beside themselves at the way their marriages, once so idyllic, are now boiling with pain. Each responds in different ways: Howell's wife drinks herself to sleep on a couch; Buchanan's husband tries to smother her with love, after their pastor implies he is at fault for her infidelity.

It happens with extreme speed - the contemporary appetite for lingering gratuitously over suffering isn't indulged in this enjoyably nasty murder-no-mystery, and in the end the only characters we ever really come to know are Howell and Buchanan themselves. This is entirely apt: they've created a locked world in which all others are bit players, tolerable only in so far as they facilitate one another's pleasure. Anyone who stands in their way seems likely to feel the wrath of God.

The Secret plays on TV One, Wednesdays at 8.30pm