There’s a formula to creating a good story and director M. Night Shyamalan seems to enjoy missing the mark, evident in previous work like “The Visit” and that one movie where something is “Happening” but nothing actually happens. His latest film, “Split,” promises eeriness and thrill, though it doesn’t hold out.

The story follows three girls who are abducted by a man named Kevin (James McAvoy). It is quickly revealed that he’s not just Kevin, but also Dennis, Patricia, and at least 21 other personalities as he struggles with Dissociative Identity Disorder (DID). They are preparing for their final houseguest, referred to only as “The Beast.”

Shyamalan’s poor scriptwriting is the film’s only flaw. Simply put, the performance by James McAvoy is well-done. There’s investment on his part to make obvious differences in the characters he portrays. Anya Taylor-Joy, who plays Casey, is interesting to watch and easily immerses herself in the protagonist. The effort in keeping her character “detached” as she remembers her own life battles throughout the film is noticeable, as her dull eyes and hidden pain expression make her seem “not all there.”

The letdown was also not seen in the atmosphere. There’s an obvious mood correlated to staging, and the lighting–or lack thereof in some scenes–was played right and used effectively to create a mysterious aura and give a sort of “empty” and chilling feeling.

The story, however, drags so, so slowly and strays from the plotline that I forgot I was supposed to be “thrilled.” Shyamalan is so obviously obsessed with creating an entirely different diagnosis for DID that I wonder why he doesn’t just up and make the whole show a merchandise. To make matters worse, the “twist” to the movie is evident, so much so that the whole time I sat there, I was simply waiting for it to happen. There was even a sense of dread, as this once believable movie veered out of sight and ran off on its own.

Besides Casey, two girls coexist with her for a time and are set on escaping. Such characters are more like props, proven by the fact that I can’t even remember their names. All they do is tell girls who live a normal life that they’re doomed and aren’t worth saving.

Besides being kind of misogynistic, let’s not forget the fact that real people live with DID and are only fictionalized to be violent to move horrific plotlines like this one along. The sequences that reveal both Kevin and Casey are devastatingly real, and while one could see this as giving credit, I don’t believe the exploitation of other people’s traumas deserves it.

With or without causing damage to tons of people, it’s more thrilling to put “Split” down than it is to watch it.