Requiem might read like any other psychological thriller – but weaving in supernatural undertones leads it into unfamiliar territory, say its cast. Gemma Dunn finds out more

WHAT if you want to find out who you really are - but you don't like the answer? That's the question posed by the creators behind BBC One's new psychological thriller series Requiem. The six-parter tells the story of Matilda (played brilliantly by Lydia Wilson), a talented London cellist whose life is turned upside down by her mother's inexplicable suicide.

Now questioning everything she thought she knew about herself, she embarks on a quest - along with best friend Hal (Joel Fry) - that leads her to a small Welsh town where a toddler disappeared 23 years earlier. It's there that things take a mysterious turn.

"I've never been a big fan of chainsaws and monsters, but I've always been an enormous fan of the more low-key, psychological horror thrillers that toy with an audience's and the protagonist's psyche," notes writer Kris Mrksa, who penned the identity-crisis drama following the death of his own mother. "The Innocents, Truman Capote's version of The Turn Of The Screw, is a really wonderful film. That had a big influence on my thinking. Other masterpieces that have the same ambiguity are Don't Look Now and Rosemary's Baby, which sits in terrifying, disquieting territory. That was something I was trying to land with Requiem."

It goes without saying that a bold tale requires bold characters - and Requiem, with its supernatural undertones, has them in abundance. Paving the way is Matilda Gray, who in the wake of tragedy swaps her Tinder habit and rollies in favour of going after "the real her".

"Something huge is missing from her life," says Wilson, who's also starred in Ripper Street and Star Trek Beyond. "A lot of twenty-somethings are looking for something in external images, but an integral part of Matilda is empty."

Meanwhile Hal is "a wet blanket", says Game Of Thrones star Fry. "He loves Matilda, but it's hard to tell if she knows that. But when they go on this quest together, they reach a new level of intimacy."

Also in the picture is Janice Gray, Matilda's troubled mother portrayed by Joanna Scanlan, while the Welsh town's residents, among others, include antiques dealer and "shape shifter" Sylvia, helmed by Game Of Thrones actress Tara Fitzgerald; and retired detective inspector Stephen Kendrick, played by Downton Abbey's Brendan Coyle.

In addition to housing a number of eclectic characters, the small-town setting was deemed a metaphor for isolation. A space cut off from city life.

"In the first episode I was like, 'Boom! She's from London', and then in the second and third I was like, 'I don't know who I am' - and that's what happens to her," recalls RADA graduate Wilson. "She kind of gets spread out, and is without her apps and her little accoutrements that we all need to make us feel like we've got identities, in a superficial way. It was interesting letting all of that go. It was like going back in time."

"I wanted there to be a clash of two worlds," explains Mrksa. "When I visited Wales, I fell in love with the place. It has a mystical feel, and the history there is very palpable. The Welsh town becomes a character in its own right. It's the perfect setting for this drama."

While Requiem steers clear of in-your-face horror, there's certainly spooky moments to be had.

"We can really get the psychological part of the drama - Matilda is grief-stricken," says Wilson. "She has a very thin skin because of this rupture in her confidence and she becomes this lightning rod for things that are happening without necessarily being able to read the situation. That's a spooky place to be anyway, so for me, that's where the chills come from."

"Spookiness is in the eye of the beholder," Coyle says. "We are all about the intentions and this parallel reality with the characters, their intentions and what the truth is. That is the seed."

Proving life really can imitate art, however, the scares didn't always end when the cameras stopped rolling.

"There were lot of incidents with birds!" remembers Fitzgerald. "They seemed to be in people's front gardens a lot more than normal."

"Everyone got a sty in their eye as well - and they aren't contagious!" adds Wilson, who recalls a full-on shoot of 12-hour days over four months. "I also woke up with sand in my bed in the shape of an angel. It was so weird. I took everything apart in my apartment and did all these experiments to see if it was a crushed vitamin or something."

On set, filming in an old country house conjured up some fear? "It was really quite strange and spooky," Fry confesses. "It's one of those old houses where you walk in and can't help feeling, 'What kind of things have happened here in the past?'"

It's that fascination, that desire to explain the unexplainable, that the cast believe will intrigue viewers.

"The mystery of life is riveting," begins Fitzgerald. "We're all searching for the answers to the Great Unknown. It's a very human quest: Why are we here? Where are we? In Requiem, Matilda is searching for her identity. But on a larger level, it's about how we are all looking for our place in the universe."

"In this day and age, drama can be homogeneous and formulaic," Wilson says. "I love to watch formulaic dramas sometimes and know what I'm going to get. But at the same time, I think it's great to do something like this, which is uncomfortable and unfamiliar. It's fantastic to make something that is so bold."

  • Requiem premieres on BBC One on Friday