The Walking Dead star Lennie James is set to lead Nightswimming, a brand-new ITV crime thriller from Harry and Jack Williams, the creators behind The Tourist. Set in Portugal, the drama follows a man who returns to the place where he was convicted of murdering his family, determined to uncover what really happened on the night that changed his life.

James, best known for playing Morgan Jones in The Walking Dead and its spin-off Fear the Walking Dead, will take on the role of Matthew, a father whose wife and two teenage sons were brutally attacked in their beachfront home. The tragedy took place while Matthew was out swimming in the ocean, part of his usual nightly routine, but he was later convicted of murdering his family.

Now, ten years later, Matthew returns to Portugal to investigate the crime himself, revisiting the people and places connected to his family’s deaths as he searches for answers. As he begins questioning old friends, confronting broken relationships and challenging those involved in the original investigation, he discovers that someone close to him may know more than they’ve admitted.

What Is ITV’s New Drama Nightswimming About?

Told across two timelines, Nightswimming will explore the events leading up to the murders alongside Matthew’s present-day investigation, gradually revealing what happened to his family and the circumstances surrounding his conviction.

The drama comes from screenwriting brothers Harry and Jack Williams, whose production company Two Brothers Pictures is responsible for television favourites including The Tourist and Fleabag. Their previous work includes The Missing, Baptiste and Liar, so they’re certainly no strangers to a good mystery.

Speaking about his new role, Lennie James said: “I am very excited about getting going on Nightswimming. It’s a juicy, grownup thriller about family, love, loss, betrayal, redemption and the price of justice. Matthew is the kind of character I love to play, full of complexity, contradiction and conviction. This is top notch storytelling, and I’m chuffed to be a part of it.”

James recently won a BAFTA for his performance in the BBC adaptation of Bernardine Evaristo’s Mr Loverman, and has also appeared in Line of Duty, Save Me and Mayor of Kingstown. His new role will see him return to ITV following his appearance in the 2009 drama The Prisoner.

Harry and Jack Williams also shared their excitement about the project, saying: “We absolutely relished writing Nightswimming, it’s a small-town thriller with a morally murky edge, grounded in a knotty, complex character. We can’t wait to work with ITV again and to see what Lennie – who we are thrilled to have on board – does with Matthew when we begin filming in Portugal next year.”

When Will Nightswimming Be Released on ITV?

Filming for Nightswimming is scheduled to begin in Portugal in spring 2027, although ITV has yet to confirm an official release date. Further casting announcements are also expected as production approaches.

The series will be produced by Two Brothers Pictures, with Harry and Jack Williams serving as executive producers alongside Daisy Mount, Sarah Hammond and Lennie James. Georgina Lowe will produce the drama, with Banijay Rights handling international distribution.

For CultureCues, this is definitely one we’ll be keeping an eye on. We’re big fans of Lennie James, who has given us some brilliant performances over the years, and it’s great to see him taking the lead in another crime thriller. With the Williams brothers behind the story, Nightswimming already sounds promising. We can’t wait to get stuck into this mystery and find out what really happened that night.

Nightswimming will begin filming in spring 2027, with an ITV release date yet to be announced.

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