Three extraordinary individuals, Elijah Price, David Duke and Kevin Wendell Crumb (Samuel L. Jackson, Bruce Willis, James McAvoy) are apprehended and held in a psychiatric hospital. Here they’re examined by a specialist in people who believe they’re superheroes (Sarah Paulson), in this film by a person who believes he’s a film director (M Night Shyamalan).

This is a follow-up to Shyamalan’s Unbreakable and Split, but thematically it’s closer to the former, which dealt with Elijah’s obsession with real-life superheroes and his discovery of David, AKA The Overseer, who possesses super-strength, spidey senses and an anorak.

It does have a few decent ideas, but rather than exploring them through a compelling narrative, the characters sit around talking about them for the first two thirds of the film; the desire to save big plot developments for final-act twists starving the rest of the film of incident.

This exposes Shyamalan’s limitations as a writer. In a film where nothing happens you need strong characters to make it work. Unfortunately Willis, in spite of giving his most committed performance for some time, is still closer to a rock than The Rock, and McAvoy’s 23-personalitied Kevin is basically just a vehicle for wacky cartoonery. This leaves Jackson’s brittle-boned genius carrying all the weight.

Each of the three “heroes” has a concerned friend or family member who visits the hospital: Elijah’s mother (Charlayne Woodard, who looks the same age as him and is 5 years younger than Jackson in real life); David’s son (Spencer Treat Clark); and, in a role-reversal as absurd as the woman who was almost dinosaur food in Jurassic World becoming a dinosaur rights advocate in Jurassic World 2, one of Kevin’s abductees from Split (Anya Taylor-Joy) is now friends with him, apparently indifferent to the fact he still abducts cheerleaders in his spare time. The trio are given nothing to do as they sit around with each other, in spite of having no reason to be in the same room.

Irish twins

Fans of McAvoy’s funny voices will be pleased to see they’re back in abundance, with a performance that’s essentially Peter Serafinovic doing 50 fake impressions in two minutes. Old favourites Patricia, Hedwig and Dennis return, with newcomers including a pair of Irish twins and an expert in Japanese cinema, who share the character trait of saying “I’m so-and-so” when they take over Kevin’s body, like hypnotised Homer Simpson.

It’s irritatingly filmed in darkness and close-ups so we often feel like we’re missing the action, which is a shame given how long it takes to get to it. This means that a film which could have been fun is largely a snooze-fest. It takes itself so seriously that McAvoy’s comedic performance feels strange and out of place. Too long, boring and limited in scope, Glass’s ideas are stretched to breaking point and instead of being a smash it just blows.