When it comes to crime fiction, Scottish author Val McDermid knows a thing or two.  

The revered and prolific writer has quite the track record when it comes to producing crime bestsellers, with each book of her series and standalone publications gifting readers a myriad of memorable plots, characters and twists.

Even if you’re not au fait with this crime-writing mastermind, you may well have watched a show or two based on her works and ideas, including Wire In The Blood or the more recent Traces.

So when it was announced that McDermid’s iconic detective, Karen Pirie (known to fans across a series of six bestsellers), would be making the leap from page to screen, the denizens of both telly-land and book-world took notice.

And now, Detective Sergeant Karen Pirie is hitting our screens in the fictional flesh. Based on the first book in the series, The Distant Echo, and starring Lauren Lyle (Outlander) in the title role, this show is all set to be your new favourite crime watch.

But who is Karen Pirie? What crimes are afoot? And who’s among the supporting cast? Read on to discover all this and more...

What’s the story?

Young, tenacious and brusque (sometimes to a fault), Karen Pirie is a police detective living and working in the beautiful coastal town of St Andrews, Scotland.

But small-town life doesn’t mean small-town crime, and a series of cold cases find their way to Pirie. And while seagull-corralling and deckchair squabbles have their charms, there’s no one better placed – or more willing – to do the job.

In a nod to a real-world phenomenon, episode 1 finds Pirie tasked with reopening a case long thought cold following the release of a revealing – and provocative – true crime podcast.

The case in question centres on the brutal 1996 murder of teenager Rosie Duff (Anna Russell-Martin). Suspicions fell on three students discovered at the scene, but owing to a lack of forensic evidence, no one was charged.

In the present day, mysterious goings-on hint suggest that someone has long been pulling strings to keep the case sewn shut. But they didn’t reckon with the formidable investigative force poised to pry apart the sutures 25 years on.

Karen who?

Pirie is a gifted detective newly assigned to Police Scotland’s Historic Cases Unit. With a proclivity for brutal honesty and quick (though often on-the-money) surmising, she’s a force to be both respected and reckoned with.

According to Lyle, Pirie’s “dry wit and attitude of not giving a damn are exactly the same as in the book”. The 29-year-old actor, who also appeared in last year’s BBC submarine drama Vigil, says: “I watched loads of female detective shows for my research and many of them tend to be about damaged women who are going through something and their job is their life. [Writer and co-star] Emer Kenny and I decided we didn’t want her to be a sad detective. She’s so determined and she’s right at the start of her career, as well as having to fight the battle of a conservative traditional male police force.”

Who else is in the cast?

A slew of top actors appear alongside Lyle: as well as Kenny (Harlots) as Karen’s friend River Wilde, there’s Chris Jenks (Sex Education’s Steve) as Jason Murray and Zach Wyatt (Blithe Spirit) as DS Phil Parhatka.

Young actors Jack Hesketh, Buom Tihngang and Jhon Lumsden play the three students originally suspected of Duff’s murder; they’re seen in flashback, while Michael Schaeffer (The Salisbury Poisonings), Ariyon Bakare (His Dark Materials) and Alec Newman (Unforgotten) play the adult versions of the characters.

Where is it set?

The majority of filming took place in St Andrews and Glasgow, as executive producer Simon Heath explains: “While the main Scottish production base is in Glasgow (which is where we based ourselves) we made sure we had a significant chunk of time to shoot all the key exterior scenes in St Andrews.

“This was vital – the setting of St Andrews is unique. It’s a university town, which attracts a lot of posh English students, creating a potentially volatile ‘town and gown’ mix. The story trades on this unique setting.”

The setting for Karen Pirie really does have to be seen to be believed. “It’s beautiful having the series set in Scotland,” says Lyle. “Some of the landscapes we have are phenomenal, up in Loch Lomond and in the mountains. A friend of mine has watched some of the series and kept asking if we’d used CGI. I kept saying, ‘No, that’s just Scotland!’”

How long is each episode?

Each of Karen Pirie’s three episodes has a runtime of two hours. For Heath, the longer episode length allowed the story to breathe.

“The more we thought about it, the more we could see the benefits. The Distant Echo is a big book with a lot of story. With two timelines, plus the character dynamics and Karen’s relationships, it was difficult to see how all this could be accommodated in 47-minute episodes. The two-hour slot gave us enough screen time to cover all this and more.”

Rest assured, those two hours will fly by thanks to the series’ excellent pacing, characterisation and writing, while the irresistible mystery will have you hooked from the off.  

When is ITV’s Karen Pirie on TV?

The first episode of Karen Pirie airs at 8pm on Sunday 25 September on ITV HD (CH 113/103). Episodes will also be available in Apps & Games > ITV Hub.