Kevin McKidd on new Glasgow-filmed ITVX drama Six Four

For Scottish actor Kevin McKidd, filming the tense new Glasgow-based ITVX drama Six Four was a bit of a “homecoming”.

“It’s been great. It feels like a homecoming for me,” says the Trainspotting star, who made a name for himself Stateside as Dr Owen Hunt in the long-running US medical drama Grey’s Anatomy.

“And I love working over there (in the US) and the crews and actors are brilliant. But there’s something that just feels really familiar, there’s a shorthand that exists, I think, in British crews and British actors, between us all, that you just kind of know.”

The 49-year-old – who joined Grey’s Anatomy in 2008 – “jumped” at the chance to be part of Six Four, by Scottish playwright and screenwriter Gregory Burke, admitting he’s “really missed” working on this side of the pond.

“So, it’s been lovely,” he adds. “And I really love Gregory’s writing.”

The four-part crime drama is inspired by the Japanese novel of the same name by Hideo Yokoyama, centred around a historical kidnapping and police cover-up, which is brought to the surface when, years later, a detective’s daughter goes missing.

For the series, which debuts on ITV’s new ITVX streaming service later this month, Burke has taken the key themes and plot points but created a new version of the story, based in Glasgow.

It centres on Scottish detective constable Chris O’Neill and his wife Michelle, whose lives are upended when their 18-year-old daughter Olivia goes missing, after she finds out that Chris is not her biological father. Set against a backdrop of a marriage in crisis, their desperate search causes a series of secrets to begin to unravel.

Chris and Michelle must face the truths they’ve been hiding (including Michelle’s past as an undercover police officer and Chris’s affair with a journalist called Samantha) and in the process confront a wider picture of lies and corruption, involving the cover-up of the tragic disappearance of a local girl called Julie 16 years earlier – the daughter of Jim Mackie, a former lawyer and friend of Robert Wallace, justice minister in the Scottish National Party.

Samantha becomes more closely involved when she is tipped off about details linked with the case and things get increasingly dark and twisted.

Both McKidd and Vinette Robinson, who plays Michelle, were attracted to the complex layers of the story.

“It’s got all the classic elements of a political crime thriller, so it’s very twisty-turny and there’s lots of intrigue and investigation into ways power structures work, but at the heart of it is this relationship between Chris and Michelle,” says Yorkshire-born Robinson, 42, also known for shows such as Sherlock, Vera Drake and Black Mirror.

“So it makes it very relatable, and the struggles those characters are going through are very relatable. That’s what I loved about it – the juxtaposition of those two things, the human relationships at the heart of this big political drama.”

Touching on how the character’s personal journeys with secrets and the truth play out alongside a landscape of systemic corruption, McKidd says: “When we meet (Chris), he’s kind of in a midlife crisis and him and his wife are struggling through their marriage. They’re not very connected with we first meet them, and he’s not very connected to his work.”

When their daughter’s disappearance causes the historical case of Julie and events surrounding that to “bubble up from the depths”, the actor says this “reignites Chris as a detective, as a family man”.

For Michelle, the mother’s determination to protect her daughter sees her “take matters into her own hands” and “deploying skills” from her old life as an undercover officer – something she’d “put a lid on for a long time”, explains Robinson. “It’s going back into that world that makes her face some truths about herself and her relationship… She comes to terms with things through that journey.”

Echoing his co-star, McKidd adds: “I think one of the big themes in this is that the truth will always find its way to the surface, however long it’s been.

“What’s really interesting about Chris and Michelle is, because there are these lies by omission and things that haven’t been talked about for years and years in a marriage – I think many people can relate to this – it either breaks the marriage apart, or you have to actually burst through that and find reconnection through communicating.

“And I think that’s what we see these two do – and it’s painful and hard, because when untruths and lies have been there for so long, it’s hard to do that work. So, I think it’s a really beautiful depiction of a marriage, as well as a thriller.”

It’s not incidental that the series is set in Glasgow.

“Gregory obviously, his voice is very much a Scottish writer’s voice, so I think that’s where his passion lies – to create really interesting, unique work that has a Scottish voice, and I think Glasgow is a great setting for it,” says McKidd.

“Glasgow has a very sort of messy and interesting history of corruption and violence, and this is a very twisty-turny, political thriller, in a sense, so it seemed like the right place. And Glasgow is so close to beautiful countryside but also incredibly urban, and at the same time it can have a lot of edge.”

Robinson adds: “The political landscape of Scotland is quite central, but he (Burke) also manages to use that to tell a more universal story about power dynamics, the political classes.”

The actors are equally full of praise for Burke’s handling of the script.

“He’s structured it in a way that those cliff-hanger moments and plot twist moments are placed – and you know, sometimes you can get these wrong, just in the rhythm of this kind of drama, it’s not easy – and he really got it right.

“He lands those moments right at the end of the act. It’s really smartly devised and his execution of it, I think, really will keep people on the edges of their seats, wanting to know – needing to know – where this is leading.

“It’s one of those dramas that, to be honest, you’re going to have to pay attention,” McKidd adds. “It’s not one that you can just sit back and let it wash over you – you have to keep up with it.

“It’s complex, it’s dense, but it’s very entertaining and very compelling.”

All episodes of Six Four will be available to watch on ITVX from Thursday, March 30.