“Derailed” has its share of plausible hooks. A thriller with a twist that critics won’t disclose, it has “Friends” refugee Jennifer Aniston trying another noncomic role. Clive Owen, the up-and-coming smolderer of “Closer” and “Sin City,” plays opposite her. The movie’s source material is a James Siegel best seller in the mold of James Patterson. And, last but far from least, it’s the proud debut production of the Weinstein Company, the successor to Miramax.

Actually watching the thing is another matter. “Derailed” rumbles along obliviously, without any finesse or logic in its buildup. Ms. Aniston and Mr. Owen seem out of place. Swedish director Mikael Hafstrom relies on a few cheap, nasty shocks, chiefly a disturbing rape scene, to force the viewer to pay attention. Ultimately, the movie only holds curiosity value as a moralizing distillation of noirish cable-TV thrillers.

The plot would be quaint for its old-fashioned morality if the details weren’t so horrifying. Adman and devoted husband Charles Schine (Mr. Owen) decides to drop the devotion one day on the commuter train. One glance at the gams of Lucinda Harris (Ms. Aniston) leads to a flirtatious conversation, then lunch and dinner. When they move on to a hotel tryst, horror strikes: A thug (Vincent Cassel) crashes in on them mid-clinch, brutally beats Charles, and, from what Charles can tell in his half-conscious haze, sexually assaults Lucinda.

Afterward, the sadistic thug (named Laroche) repeatedly blackmails Charles for thousands of dollars. But the lovers refrain from calling the police lest their spouses learn of the infidelity. Charles gets beaten up some more when he tries to flout the scheme, which grows more complex.

All these elements should add up to an acceptable thriller. But the creaky plot machinery makes the movie’s nastiness seem less menacing than gratuitous. Mr. Hafstrom essentially constructs a Pavlovian exercise in warning against the consequences of infidelity only slightly less transparent than “Fatal Attraction.”

The role-seeking Ms. Aniston, in her attempt to overcome her congenital perkiness, has become an unwitting party to Mr. Hafstrom’s scheme. In “The Good Girl,” she tried a slack-faced performance that only postponed the question of her dramatic chops. After “Derailed,” we still don’t know: The sexy-cool scenes with Mr. Owen are rather mechanical, and she appears but little after the rape scene. As for Mr. Owen, it’s frankly dispiriting seeing a man of his quietly suave manner and intelligent presence being put through such manipulative motions. You feel a little sympathy for the skilled “Croupier” star, who drops his English accent for a Nicolas Cage drone.

Mr. Hafstrom obviously has very specific ideas about the Big Scary City, but his take on the thriller’s turf, Chicago, is a European rebroadcast. Charles of course has a street-savvy black mailroom attendant (The RZA). And who knows what to make of the mysteriously French thug Laroche, who in Mr. Siegel’s novel is a Hispanic man named Vasquez?

As for the twist, most viewers will sense something awry and foresee the (suggestive-adjective spoiler!) Mametian shift. It divides the movie into two phases: slimy and mediocre, and just mediocre.