An hour of brooding atmosphere and half-hour of silly revelation pretty much sum up Halle Berry's supernatural thriller "Gothika."

A decent cast, a creepy setting and an intriguing story idea ultimately go to waste, with "Gothika" devolving into a muddle of twists and turns as it desperately searches for a third act and comes up empty.

While the movie aims for class early on with the promise of a thoughtfully understated ghost story — in the manner of "The Sixth Sense" or "The Others" — "Gothika" eventually falls back on a cheap-thrills payoff, and not a very good or scary one at that.

Berry plays Miranda Grey, a psychologist who treats violent criminals at a prison psychiatric ward run by her hubby, Douglas (Charles S. Dutton).

Tautly paced opening sequences by director Mathieu Kassovitz and screenwriter Sebastian Gutierrez skillfully establish the Gothic-castle feel of the dark, hulking prison, along with the key players — Pete Graham (Robert Downey Jr.), Miranda's puppy-eyed colleague who's clearly in love with her; Sheriff Ryan (John Carroll Lynch), Douglas' fishing buddy; and Miranda's patient Chloe (Penelope Cruz), who rants that Satan stops by her cell to rape and torture her.

Driving home one rainy night, Miranda must take a detour over a narrow wooden bridge, where she encounters a vision of a mutilated girl who bursts into flame. Three days later, Miranda wakes up in a cell at her own psych ward, accused of savagely killing her husband with an ax, a crime about which she has no memory.

There's potential for a tingly descent into cloistered madness here, but the filmmakers don't know where to turn with the story after a handful of chilling manifestations as Miranda slowly uncovers the identity of the burning girl in her vision.

The movie builds tension for a while, as supporting characters waffle from suspects to sympathizers, with most of them becoming red-herring appendages.

"Gothika" also leaves behind ludicrous loose ends in terms of who actually did what. And from its tacked-on epilogue, the movie clearly exists in a realm where possession by spirits from beyond is a viable legal defense.

Before he's snuffed, Miranda's husband tells her, "The ability to repress is actually a vital survival tool."

The key to surviving "Gothika": Repress the urge to buy a ticket.

"Gothika" is rated R for strong scenes of suspense-thriller violence, scattered use of strong sexual profanity and female nudity. Running time: 98 minutes.