With Line Of Duty fanatics patiently awaiting a new series, 'Irish noir' Bloodlands may function as the ideal warm-up. Jed Mercurio takes on executive producing rather than writing duties on this four-parter, but there are still a number of tentacles connecting it organically to the overwrought and often shakily-performed tales of AC-12 and co (sorry, not a fan). There's a twisty turny plot; the coarse stench of powers-that-be who aren't as squeaky clean as they should be; and, of course, there's always an initialism, abbreviation of acronym to keep you on your toes. Thankfully, Bloodlands only features one, though it is mentioned at least eight times per episode. As a character notes, 'someone came to see me; it was a long abbreviation'. Dear viewers, welcome to the world of ICLVR.

That group is a vaguely shadowy wing of the Belfast police force which here is investigating two things that may or may be connected (not a spoiler: they almost certainly will be). Even more shadowy than ICLVR is the non-initialised Goliath, a secret assassin who 20 odd years ago committed murders that had to be kept quiet in case they disrupted the fragile peace process (while this is all fictional in Bloodlands, it's not a great leap to imagine that such events actually occurred in the late 90s). The investigation into those crimes is opened up again, with it dawning on all and sundry that this is a deeply personal matter for DCI Tom Brannick (James Nesbitt). Meanwhile, an ex-IRA operative has been kidnapped for reasons that are unclear, but when Brannick looks into that, the abductee's wife is somewhat unhelpful.

A large aspect to enjoying Bloodlands hinges on the audience's appreciation of James Nesbitt. An actor whose CV is filled with comic drama as well as actual proper serious drama, his stoic dignity is fully intact here while flashes of the old cheeky charm are also present and correct. While it rather clumsily sets up its row of conspiratorial ducks, the series offers much more than Line Of Duty ever did in the way of authenticity (its rigidly Northern Irish cast certainly aids that cause). And by the end of episode two with its, yes you guessed it, amazing twist, you're unlikely to resist following through to the conclusion.

BBC One, Sunday 21 February, 9pm.