It used to be that when an actress took on a role for cred (remember Jessica Lange in ''Country''?), she did all that she could to tone down her glamour. Yet watching Meg Ryan in the swankily dank erotic thriller In the Cut, it's a challenge, truly, to fixate on anything past her hair. Ryan, cast as a morose English teacher who is scared of everything that attracts her, wears her locks in a severely straight, reddish-brown helmet (think Heidi Klum meets Annie Hall), and her pixie features all but disappear beneath that stylish intellectual mop. This movie seems to be saying that if you're a commercial actress concerned about shoring up your status in Hollywood, then cred, in all its Oscar-bid glory, is just a rinse job away.
''In the Cut,'' adapted from Susanna Moore's popular novella, opens with a lullaby version of ''Que Será, Será'' that is so discordant, it sounds as if the piano player had an upset stomach. The tuneless dread is matched by the broken-mirror images, as the director, Jane Campion, splinters lower Manhattan into fragments of depopulated grunge. There are back alleys, bohemian tenements, and the occasional strip club, all shot in glowing sunset tones with a wavery handheld camera. Yet the locations are as solemn and deserted as a mausoleum. Technically, this may be New York City, but it's been stripped of all organic hustle and bustle, as if Campion were shooting an expressionist version of ''Eyes Wide Shut.''
The atmosphere of hushed, hermetic paranoia extends to the borderline ludicrous story, as Frannie Avery (Ryan) wanders into the basement of a gloomy bar, where she observes a man in the shadows receiving oral sex from a woman with blue fingernails. In the novel, Moore describes this moment matter-of-factly, with her heroine flippantly evaluating the other woman's technique. In the movie, it becomes a primal scene of male domination, as if Frannie were a trembling virgin who'd descended into hell. ''In the Cut'' is one of those potboilers in which a homicidal slasher is on the loose and the man our heroine is sleeping with may or may not be the killer. In this case, that would be Detective Malloy (Mark Ruffalo), the gruff puppy of a cop who's investigating the case. Stripped of Moore's eager, exploratory prose, ''In the Cut'' has, in essence, become a dreadfully inert late-night cable movie, complete with cheesy coincidences and dismembered limbs. It's ''Forbidden Sins'' inflated into a ''myth'' of victim feminism.
Ryan and Ruffalo have a bedroom scene in which the actress disrobes, sans body double, but Ryan, unfortunately, appears no more aroused than if she had been a body double. Her affectlessness may suit Campion's design. The once-great director of ''The Piano'' has succumbed, in the last decade, to a kind of stultifying didacticism, and that trend reaches its nadir with ''In the Cut,'' a movie that strains, and fails, to be lurid even as it wags its finger at anything that resembles sin. Everywhere that Frannie looks, she sees omens of sexual violence, yet Ryan radiates neither desire nor terror. She's freeze-dried in a world of lifelessly abstract feminine fear, and so is the movie.