SOMETIMES the location of a TV show can become like a character in itself. That's certainly the case with BBC One's Shetland, which is set against the striking backdrop of the Shetland Islands.
Made up of more than 100 islands (just 15 of them inhabited), the remote archipelago lies 100 miles north of the Scottish mainland.
With dark, wild winters, stormy seas and skies and dramatically rugged coastline, it's a beautifully bleak place, which only adds to the notable Scandi-noir feel to Shetland, inspired by Ann Cleeves's award-winning novel series of the same name.
In the upcoming fifth season, DI Jimmy Perez – played by Glaswegian Douglas Henshall – uncovers a complex network of organised crime. Once again, he faces plenty of obstacles, both in terms of the cases and his relationships.
"The challenges are the same – getting people to trust him," notes Henshall (53), who's also known for science-fiction series Primeval. "When you live alone and you live for your job, how do you manage to stop yourself getting really badly wounded by what it is that you do? You have to be able to keep the job at arm's length sometimes and I don't think he's very good at that."
Each series of Shetland focuses on a new investigation. Series five begins with a young man waiting patiently for someone on a "windswept hillside", before tentatively approaching a vehicle which appears.
A few days later, a jogger on her morning run makes a shocking discovery – a severed hand on the beach.
A holdall containing further body parts is found, the victim is identified as a young Nigerian man, and things take an even darker turn as Perez and his colleague start looking at his final movements and scrutinising his social media accounts and email.
Alison O'Donnell, who plays DS Alison 'Tosh' McIntosh, and Steven Robertson (DC Sandy Wilson) return alongside Henshall.
An old friend of Perez's will be returning to Shetland, and there are some harsh truths coming his way thanks to her.
"She knows him very well, and there's probably not a lot of people who are prepared to say the things to him that she says," Henshall says. "And she's right. So yeah, I think she absolutely nails him."
Fans of Shetland will remember Perez is a widower – series one began with him moving back to the island to create a secure home for himself and his daughter, Cassie, following the death of his wife Fran.
We've seen him try to bring her up the best way he can, and get on with life as a single father. But when asked whether any romance could be on the cards for his character this year, Henshall, himself a father-of-one, teases: "I don't want to say too much but it looks like it might be wonderful. But that doesn't always mean that it will be."
So what is it about Shetland that, at a time when TV and streaming services are packed with first-rate crime dramas, keeps bringing viewers back?
"I think it's maybe to do with the fact that the writers of our show have really hit their stride as far as these characters and the format is concerned," says Henshall.
"One of the benefits of a long-running show is that the public get to care about these people and care about what happens to them."
He adds: "The writers get to properly explore the characters over a period of time; it's not like they're having to cram everything into one go and that's it.
"They get to put people in real situations and explore what they're like.
"I think ultimately the public care about characters; it's the characters that people like. Audiences have had six years to build up a relationship with these people and I think they're hooked now."
When it comes to what the role means to Henshall, it's a character that he continues to feel a kinship with.
"I think, regardless of who you play as an actor, you have to empathise with them, otherwise you wouldn't be able to play them with any degree of justice," he says.
Much of Shetland is shot on the Scottish mainland but Henshall filmed on Shetland itself for six or seven weeks.
"It's great, I love going there," he says. "Our crew are fantastic. It was a really nice bunch of people and we got on very well. When you're working very hard and the elements are against you, it draws people very close."
Because the cast and crew travelled to Shetland in summer for the first time in a long time, Henshall saw first hand how the show has boosted tourism.
"The amount of people who are coming to Shetland now as a direct result of the show is astounding," he says. "Apparently since we started the series, the amount of people who are coming has gone up by 40 per cent year on year – it's nuts!"
:: Shetland returns to BBC One on Tuesday February 12.
