Bradford-born actress Vinette Robinson and Kevin McKidd on new ITVX crime drama Six Four

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 Robinson, 42, from Bradford and 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, who earned critical acclaim and a British Independent Film Award for best supporting actress for her role in the 2021 movie Boiling Point (and has also been cast star in a television series based on it).

“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.”

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