Is James McAvoy’s improvised thriller the strangest Covid movie yet?

The pandemic has subjected us to a brave new world of cinematic experiences: a seance horror on Zoom, Anne Hathaway trying to rob Harrods, Naomi Watts taking phone calls in a forest, films that have shown either admirable ingenuity during an impossible period or that it’s really OK, nay better, at times to just put your tools down and bake banana bread instead.

The majority of them have been rather wretched (laptop horror Host a notably nifty exception) but often fascinatingly so, shambolic curios that live and die in this unusual chunk of time, never to be watched or thought of again. Yet none of them have quite matched the sheer what-the-actual-fuck-is-this oddity of My Son, a film you’ll most likely not have heard of because *whispers* they don’t want you to know that it exists. But exactly why would a thriller starring James McAvoy and Claire Foy be treated like toxic waste?

To understand its bizarre journey to the bottom of the streaming drain, one must go back to 2017 when French thriller Mon Garçon introduced a unique concept to a generic subgenre. In the film, Guillaume Canet was given just a six-page character outline and told to improvise his way through the familiar story of a man looking for his son. Other actors had a more complete script but the success of the film largely rested on Canet’s experienced shoulders. It was Taken but what if the script had gone missing too. The film was a modest success in France and received mixed-to-positive reviews when released in the US, a gamble that paid off enough for the director, Christian Carion, to want to do it all over again.

In October 2020, when film production was possible but precarious, it was announced that Carion would be partnering with STX for an English-language remake, filmed in Scotland with McAvoy taking on Canet’s role and Foy as his ex-wife (a character played by Mélanie Laurent in the original). The gimmick would remain and McAvoy would have to freestyle his way from lost to found, a predicament that would create “real tension” according to those involved. Cut to almost a year later and the film is now being chucked on to Peacock, NBC’s streaming service in the US, for a three-month period before being offloaded on to the Roku channel, like a three-course meal being deliberately dropped on the ground and left for the raccoons.

Screeners were offered to journalists before swiftly being denied so I bravely logged on to Peacock and fished it out of the trash myself, curious to follow and investigate the rotten stench. The recently released trailer clues us into the gambit with text referring to it as “a groundbreaking film-making achievement” (that’s been done before) with McAvoy calling it “an experience that no actor gets to have” (apart from Canet). But one of the strangest things about a project filled with many strange things is that the audience isn’t made aware of this at the start of the movie itself and so for most people who stumble on to it, the “groundbreaking” element will be a secret. For those who do know, it’s at least a valid explanation for why the film is so very bad, its stilted, on-the-fly dialogue and paper-thin plot justified by the improv class nature of it all.

For McAvoy to solve the mystery, it’s one that has to be kept as basic as possible, which makes sense for him, the actor, but for us, the viewer, it makes an already rote premise feel even more uselessly mechanical. The nature of the film turns it into an incredibly joyless video game, McAvoy playing a character who we would usually be in charge of, going from location to location with actors revealing clues that propel him to the next scene. He’s an accomplished performer so even in the film’s shoddiest moments he’s never exactly bad, but taking on the role of screenwriter is an understandable stretch, every line either boringly perfunctory or laughably messy (“Either he knows something or he’s criminally a fucking prick” was worth a screengrab). The bullish hubris of My Son, which suggests a feature-length thriller can essentially be scrambled together out of thin air by an actor rather than one of those useless writer people, predictably crumbles as we go through the very dull motions of a very dull film. There’s not a single revelation or scene or line of dialogue that rises above the level of sub-average and there’s no amount of dramatic thriller score or sweeping Scottish scenery that can distract from the rot of a project that was cursed from the outset.

One can understand why McAvoy was attracted to it, a chance to challenge himself as an actor at a time when work was also thin on the ground (he also starred alongside Sharon Horgan in Stephen Daldry’s quarantine comedy Together). But the entire film places the viewer’s experience at the very bottom of the list, as if our enjoyment is of little to no interest, and instead we should feel honored to sit in on an indulgent and deeply, punishingly uninteresting acting class.

There’s not even a how-bad-can-it-really-get train wreck appeal to the film – it’s far too boring for that – and so its descent from the big screen to the streaming netherworld feels like a justified mercy killing. They didn’t want you to know about My Son for a reason. I apologise for telling you.

• My Son is available on Peacock in the US with a UK date to be announced