If you hear that M. Night Shyamalan has released a new superhero movie and don’t let out an audible groan, you’re likely one of two people—someone who hasn’t seen many movies since 1999, or someone who enjoyed Split, Shyamalan’s surprise 2016 hit starring James McAvoy as a hypnotic supervillain with 24 distinct personalities. Although plagued by a particularly bad case of mental-illness-as-horror, Split succeeded in ways that no Shyamalan movie had in years, due in large part to McAvoy’s tricked-out performance.

Unfortunately, not even McAvoy can save the film’s sequel, Glass, from Shyamalan’s worst instincts. Despite his earnest belief in the power of his heroes, the writer/director’s self-seriousness and his need to explain himself through a clunky script sabotage the film at nearly every turn—Glass only succeeds when he lets the camera do most of the talking. As a result, what was likely meant to be a meditation on the genre comes off more like a lecture, one that will disappoint most superhero fans and skeptics alike.

Glass is the final film in a trilogy most don’t even know exists, beginning with 2000’s Unbreakable and continuing, loosely, with Split. For this finale, security guard-turned-vigilante David Dunn (Bruce Willis) and his sworn enemy Elijah Price, also known as Mr. Glass (Samuel L. Jackson) from Unbreakable, are brought face-to-face with McAvoy’s charismatic Kevin Wendell Crumb from Split, whose ever-changing personas have been dubbed The Horde. It’s a jigsaw puzzle, and all the pieces are characters with three or more names.

What was likely meant to be a meditation on the genre comes off more like a lecture.

Although a gulf of more than 15 years separates the first two films, Glass takes place just three weeks after the events of Split, with Crumb continuing his pattern of kidnapping and murdering young women when controlled by his ultra-violent persona, The Beast. Enter Dunn, or The Overseer, who dons his forest green poncho, sniffs out Crumb’s lair and frees the current batch of trapped cheerleaders with his superhuman strength, only to be tossed into the same Philadelphia mental institution as Crumb and Price for delusions of grandeur. Tough break, Die Hard.

As Dunn, Crumb and Price circle one another in the world’s most poorly staffed hospital, psychiatrist Ellie Staple (Sarah Paulson) begins her work of convincing the men that they aren’t superheroes, but rather talented and unwell men. She taps into their childhood traumas to identify their weaknesses—water for Dunn, bright lights for Crumb—and uses them as a means of control, promising them freedom only when they accept their status as regular people.

At this point, the film stagnates, with each lecture from Dr. Staple feeling more grating and tedious. Dunn’s son Joseph (Spencer Treat Clark), Price’s mother Mrs. Price (Charlayne Woodard) and Crumb’s former victim Casey Cooke (Anya Taylor-Joy) each make visits to either plead the case of their companions or convince them to comply. The film’s gears only begin to turn again when Crumb and Price hatch an inevitable plan to escape, resulting in a courtyard face-off between the three supers that is decidedly underwhelming, more of a sluggish brawl than a showdown. There’s talk of visiting the tallest building in the city for a Marvel-esque battle, but we never get there—one of Shyamalan’s many winks at the camera that aren’t as subversive as he thinks.

Dr. Staple’s monologues about trauma and grandeur aren’t so different from Shyamalan’s own posturing, delivered through characters’ meta-commentary on what superheroes are supposed to do, where they come from and what we can learn from them. While Joseph, Casey and Mrs. Price form a coalition of regular people who believe in their comic-book counterparts, the film’s script gets self-referential to the point of eye-roll absurdity, with lines like, “This is an origin story.” While Shyamalan might think he’s flipping the superhero industrial complex on its head, he’s really just revealing how little he seems to know about what the genre has already accomplished without his involvement.

For viewers who haven’t seen either Unbreakable or Split—and even for those who have—massive questions linger through much of the film’s first two acts. Why are Crumb and Price enemies? Where’s the action? Why is Casey romantically involved with the man who kidnapped her? What’s up with that train accident people keeping talking about? And why is Jackson’s mother being played by an actress five years his junior? But even as the film closes in on its twisty conclusion, with biggish reveals about why what we watched mattered, the questions continue to overshadow their answers.

Despite it all, McAvoy shimmers and shines when he has the spotlight. His performance as Crumb/The Horde is a rare case of the most acting also being the best acting. It’s a total delight watching him shape-shift from 9-year-old boy to arched matron and beyond, and his scenes—with the addition of some adventurous camerawork—are the best Glass has to offer. But if you’re in it just for The Horde, stick to Split, a tighter, scarier and better movie all around—Shyamalan’s too busy sermonizing to notice your absence. ◆

Glass ★ ¹/₂ 

Starring James McAvoy, Bruce Willis, Anya Taylor-Joy, Sarah Paulson, Samuel L. Jackson, Spencer Treat Clark, Charlayne Woodard, Adam David Thompson and Luke Kirby. Written and directed by M. Night Shyamalan. At Assembly Row, Boston Common, Fenway, Seaport, Somerville, South Bay and the suburbs.