Six Four: Release date, cast and latest news for ITV crime thriller

The series is led by Kevin McKidd (Grey's Anatomy) and Vinette Robinson (Boiling Point), who star as Chris and Michelle O’Neill, a married couple whose world is rocked when their daughter goes missing.

Michelle uses her skills as a former undercover officer to try to get to the bottom of the case, while Chris, a serving police detective, is also confronted with a similar case of a local girl's disappearance that has gone unsolved.

The series not only centres on this major mystery but also involves politics, extortion and corruption making for a crime thriller like no other and an unmissable twisty must-watch.

With that, here's everything you need to know about Six Four.

Six Four release date

Six Four initially started streaming on ITVX on Thursday 30th March with all four episodes available to watch at once.

Now, the series will premiere on the linear channel, ITV1, on Sunday 22nd October at 9pm. Episodes will be released weekly on ITV1 every Sunday at the same time.

Six Four cast

McKidd and Robinson lead the cast of this crime thriller, with McKidd perhaps being best known for his role as Dr Owen Hunt in Grey's Anatomy.

Speaking about whether his return to his native Scotland marks a departure from the long-running medical drama, McKidd told RadioTimes.com exclusively: "It’s felt like a real homecoming for me and I want to do more of it, but that is not me saying that I’m leaving Grey’s anytime soon. I’ll be there for as long as they want me to be there.”

As for Robinson, she can most recently be seen in BBC One's Boiling Point, reprising her role as head chef Carly from the hit 2021 film where she starred alongside Stephen Graham.

Not only is the cast of this new crime thriller led by these very familiar faces, the rest of the Six Four cast boasts some recognisable actors from the likes of The Batman and His Dark Materials.

The cast list for Six Four is as follows.

• Kevin McKidd as Chris O'Neill
• Vinette Robinson as Michelle O'Neill
• James Cosmo as Jim Mackie
• Brian McCardie as Bill Martin
• Richard Coyle as Robert Wallace
• Alison Peebles as April Mclean
• Alex Ferns as Gordon Byrne
• Laura Cairns as Ms Fullerton
• Lorne Macfayden as Stuart Simpson
• Andrew Whipp as Philip O'Neill
• Iona Anderson as Annabel Wallace
• Frances Grey as Pauline Wallace
• Jessica Hardwick as PC McKenzie

Six Four plot

Inspired by the bestselling novel of the same name by Hideo Yokoyama, Six Four is a dark tale about the search for the truth.

Produced by award-winning House Productions (Sherwood, Brexit - The Uncivil War), the series follows Chris and Michelle as they have to reckon with the fact that their daughter has gone missing.

But Chris, a serving police detective, is then provided with a shocking revelation about an infamous, unsolved case that once divided the police when a local girl called Julie Mackie disappeared. He is then informed by a journalist about the fatal mistakes that were covered up in Julie's disappearance. When Chris revisits the case in light of his own daughter's case, he discovers glaring errors and corruption.

He's faced with making sense of what he's discovered but at the same time, his wife Michelle attempts to take control of their daughter's disappearance by going in search for her. A former undercover officer, she takes dangerous risks and follows clues that lead her into a criminal underworld she escaped from, one where vice and extortion has the power to reach the upper echelons of the Scottish political establishment.

When another girl goes missing – this time, the daughter of the Justice Minister – Chris and Michelle do everything to get to the bottom of the truth, especially since the kidnapping seems to be linked to the minister's impending political election victory.

Could the past be repeating itself, or is the explosive truth of what really happened to Julie Mackie about to be revealed?

When the series was first announced back in May 2022, acclaimed novelist, Hideo Yokoyama, said:

“I’m surprised and delighted in equal measure when people have found something universal in my work. That little boy who was so obsessed with the stories of Sherlock Holmes would be excited to hear about this. I offer my heart-felt gratitude to everyone connected with the production who decided to make this series and I can’t wait to see it.”

Is there a trailer for Six Four?

There is! Be prepared to go on quite the rollercoaster as the trailer gives a glimpse of some of the themes - like Scottish independence, police corruption and kidnap - to come.

Watch the trailer for yourself below.

Six Four airs on ITV1 on Sunday 22nd October at 9pm. All episodes are available to stream on ITVX. Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to see what's on tonight

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