At nearly 2½ hours long, “A Cure for Wellness” may qualify as the world’s longest, most agonizing teaser.

For most of that duration, the gorgeously disturbing new film by Gore Verbinski adamantly refuses to spill its secrets, which continue to mount up behind a dam of mystery so maddeningly impenetrable that it’s a wonder people don’t walk out before the climax. The fact that most of them will not is because, in all likelihood, of Verbinski’s mastery of his medium: in this case, a hybrid stew of psychological thriller and body horror.

When the dam finally does burst, in a final spurt of weirdness and transgression that happens so quickly it’s hard to process, it’s like a swollen boil suddenly disgorging its contents – messy and painful, but also a huge relief.

The fact that only some of it makes sense doesn’t entirely negate what is, in the build-up at least, a beautiful film. Cinematographer Bojan Bazelli, who previously worked with Verbinski on “The Ring” (2002) and “The Lone Ranger,” uses a palette of porcelain whites and icy blues to help create the dreamlike sense of dread and unreality that pervades much of the gothic tale.

Set in a remote Swiss sanitarium, where a high-powered American financier (Harry Groener) has inexplicably overstayed his two-week spa vacation – prompting one of his underlings (Dane DeHaan) to be sent from New York to retrieve him – the story (by Justin Haythe) does nothing but pose unanswerable riddles for the longest time. When that underling, named Lockhart, arrives, he discovers a facility staffed by Alpine automatons. (Zurich Central Casting must have sent Verbinski every extra it could find with “ability to stare menacingly” listed under “special talent.”)

Lockhart’s plans to grab his boss and head home go awry when he breaks his leg, forcing him to convalesce in what looks like a cross between an early-20th-century nursing home and Dracula’s castle. All the patients are superannuated, wandering around lethargically in long white robes or occupying themselves with croquet and calisthenics, in between receiving unspecified “treatments” in a locked wing.

The only one younger than Lockhart is Hannah (the appropriately named Mia Goth), an apparent teenager who is described by the clinic’s sinister-looking director (Jason Isaacs) as a “special case.” Hannah carries a vial of vitamin extract around with her that, when Lockhart samples it, he compares to “sweaty fish.”

That description will come back to haunt him – and you – later. But until then, Lockhart is plagued by hallucinations (or are they?) involving Hannah, eels in the mountain aquifer, and steam rooms without doors.

At one point, he and Hannah wander off campus for a beer in the neighboring village. Curiously, it seems to be largely uninhabited, except for a gang of menacing punks, a mysterious military official with a collection of World War I helmets and – despite the apparent absence of any farmers – a veterinarian. Lockhart’s encounter with the latter includes a gratuitous gross-out scene, one of several in the film.

Despite treatment that appears to consist of nothing more than mineral water, Lockhart descends into a deep fog of befuddlement, even though he eventually, like all the other patients, starts to say that he never felt better. Way late in the movie, by the time most thrillers have already begun parceling out a morsel or two of resolution, you will still be scratching your head and wondering just what in God’s name is going on.

Holding that tension for so long is a tall order. And Verbinski very nearly succeeds. The problem with “Wellness” is not the temptation to throw in the towel before the finale, or even the finale itself. When the climax does come, it arrives with a bracing blast of campy absurdity so flamboyantly deviant that it glows with a kind of perverse brilliance.

But the setup to it is starved of logic, the film’s vital oxygen. Like Lockhart, you may stagger out of the theater feeling invigorated and slightly confused.

A Cure for Wellness

Playing at Stadium 9

Rating: R

Genre: Mystery & suspense

Directed by: Gore Verbinski

Written by: Justin Haythe

Runtime: 2 hr. 26 min.

Rotten Tomatoes Tomatometer: 36%