There really is nothing better than a good thriller, but we do have to admit that it takes a lot to blow us out of the water these days when we’ve seen so many twists.

But James McAvoy’s newest film offering, My Son, is something we’ve truly never seen before.

The premise may sound deceptively simple: the 7-year-old son of an estranged couple goes missing from a campsite, and it soon becomes clear that the child has been kidnapped.

Except McAvoy’s role as the boy’s father is completely improvised. Yes, you read that right. 

As Empire reports, McAvoy was given no script, no specific dialogue and was only aware of basic plot details for his character. The remaining cast and crew was fully aware of everything that was about to happen to him, which added to the already nail-biting tension.

The result? A shocking and unique drama we already know we’ll be on the edge of our seats for. Here’s everything we know about My Son.

As the film’s synopsis explains: McAvoy plays Edmond Murray, who gets a tearful call from his ex-wife (played by The Crown’s Claire Foy) saying that their 7-year-old son has gone missing. It soon becomes clear their child was kidnapped, and he journeys through a town where his wife lives in search of answers.

Edmond speaks to the police about his missing son, before they bring his mysterious job, which involves him “travelling to Libya and Iran” into question.

“You have reason to believe that it’s because of what I do that he’s missing?” he asks. The officer responds: “Mr Murray, I have to tell you that we’re investigating every hypothesis – including kidnapping. Would you say your work was dangerous?”

The detective is then mysteriously removed from the case, and Edmond’s work, particularly the ominous “Iraq files” are called into question.

Intriguing. 

Yes – and it trailer dials up the eeriness, promising that both actor and audience will uncover the mystery of the child’s disappearance at the exact same time.

The film is an English-language remake of hit French thriller Mon Garcon, with the leading actor, Guillaume Canet, not being given a script in the original either. Christian Carion, who helmed the original French version, is returning to direct the remake.

Clearly, this being kept in the dark is a formula that works.

In the teaser, McAvoy speaks about his experience filming the thriller, saying: “I hope we’ll give the audience something really tangible that they can hang on as this thriller rattles on.”

Watch it below:

My Son will be available on Universal’s Peacock streaming service from 15 September. 

Images: Peacock