Viewers gripped by a tale involving violent stranglings, mysterious Norwegians and various ghosts from the past will have been awaiting tonight's Shetland finale with a sense of real anticipation.
Over the past six weeks, the Scottish set crime show has spun another enticing web of secrets and tragedy amid its breathtaking island scenery.
Shetland may not have garnered the critical attention and lofty profile of fellow BBC crime shows like Line Of Duty and Luther, but over four consistently strong seasons it has only grown in confidence and clout.
All about the characters
What separates Shetland from the majority of police procedurals is its emphasis on the very believable characters at the centre of its stories.
The central mystery is, of course, important to the enjoyment of each tale. And this season's has been a cracking whodunnit - full of twists, turns and red herrings that are deftly set-up and paid off.
But in many ways, it merely serves as a platform for the coppers, criminals and those caught up in the saga to shine.
It has the requisite location eye-candy (cue lots of scenes on the harbour or the beach), but it doesn't rely on it.
It has some of the obligatory grittiness in its crimes and sub-plots. Yet this is frequently counterbalanced with a lot of genuine warmth and humanity from the characters. Not to mention a lighter sensibility to its cinematography, which defiantly refuses to get bogged down in darkness.
Just because this is set in the far North of Scotland, it doesn't mean it needs to rain or thunder all the time. On the contrary, a sun-soaked folk festival is as likely to kick-start the action as a wind-swept cliff. And there's far less brooding than you might think.
A multi-layered story
Season four has somewhat expanded the scope of the drama too.
Spanning six compelling episodes with a single, over-arching story, the most recent series has taken in both the luscious scenery of the titular Scottish islands, and the elegant surroundings of Bergen.
The latter field-trip to Norway helped embue Shetland with a Scandi-noir feel and through-line of its own. And no doubt stretched the budget a tad.
Tosh (Alison O'Donnell) took us on an eventful trip to Norway (Photo: BBC)
The story itself has been a little far-fetched at times perhaps. But it's also been highly immersive, multi-layered - and difficult to predict.
Shetland's latest tale has dealt with miscarriages of justice, Norwegian far-right operatives, domestic violence, small town prejudice and callous corporations.
Not all of its strands have built to potent pay-offs. But the drama has certainly excelled in the way it's handled the case of a man who may not have committed a murder he served 23 years in prison for.
The anguish of Thomas Malone, freed from jail but not his own demons. The ongoing suspicion and hatred of the community. And the desire of the cops from way down in Glasgow to nail him a second time - simply to prove a point.
Perez: a man of real empathy
It certainly helps that we really admire the cops themselves.
DI Perez (Douglas Henshall) is someone whose dogged pursuit of the truth might be cliched, if it wasn't also tempered by his commitment to his fellow islanders, his affection for his daughter, and his conflicted feelings about those who fall under suspicion.
He's stoic and tough when he needs to be, but there's a real empathy there too.
The two faces of Jimmy Perez: hardened cop and dedicated, empathetic community man (Photo: BBC)
Fellow detective Tosh meanwhile (Alison O'Donnell), is one of the drama's strongest assets. It wasn't just Perez inwardly cheering when she decided to withdraw her application for a transfer.
Dealing with her own personal baggage but prepared to dig ever further into the mire to get things done, the seriousness of her approach to her work is cut through with neat, wry humour ("he's only human" she suggests, when Perez notes a Norwegian detective has taken a shine).
Malone has been utterly heart-wrenching
O'Donnell and Henshall have been reliably strong. Stephen Walters, meanwhile, has been magnetic as the erratic, traumatised and deeply haunted ex-con Malone.
A man wracked with extraordinary inner torment and pain, Malone's every nervous tic, frantic shake of the head and outpouring of sorrow and fury has been a sight to behold.
Walters' performance has been utterly heart-wrenching. His character the poignant focal point of a deeply bittersweet tale.
The bearded, jittery Malone has faced suspicion and hostility from his fellow islanders (Photo: BBC)
Shetland has evolved heavily since it first hit screens five years ago. It started with the classic two-part detective stories British TV is traditionally known for, based on the books by Ann Cleeves.
More recently, it has adopted the kind of original series-wide plots that are a staple of modern European crime thrillers, allowing for even more intricate and in-depth character studies and mysteries.
As for tonight's season finale, it's fascinating, engrossing and palpably intense. A genuinely gripping hour of TV that spins its spell through a succession of stand-offs, interviews and revelations that have some bruising emotional pay-offs.
There's nary a misty cove or glittering shore-line in sight. Instead, it's all about the drama and the characters. And that's exactly how it should be.
Shetland series four concludes tonight on BBC One at 9pm. You can also catch up on iPlayer now.
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This article originally appeared on our sister site, iNews.