The rumors are true: “Gossip” sucks.

Some movies descend into ridiculousness. “Gossip” starts out there and just gets worse.

The premise — the nature of gossip, how it’s spread, what damage it can do — is interesting, but Gregory Poirier’s lame script and Davis Guggenheim’s style-without-substance directing completely ruin it, though at least there is some reasonably good acting along the way (not that it helps any).

Three Manhattan college students share an impossibly luxurious apartment together, as well as a journalism class. Derrick (James Marsden) is adept at spinning yarns and looking smug; his mostly platonic friend Cathy Jones (Lena Headey) has a conscience (her only character trait); their oddball roommate Travis (Norman Reedus) is a weird modern-artist with seemingly unlimited resources in the area of high-tech computer gadgetry, despite his not having a job.

For an ill-defined “Class Project,” the three decide to start a rumor and then track its progress. The rumor they choose is that while they were all at a fabulously ritzy college party (to which, apparently, no ugly people were invited, if they even exist at this fantasy university), strait-laced Naomi (Kate Hudson) had sex with her beau, Beau (the ever-puffy Joshua Jackson), in a bedroom.

Somehow, Derrick, Jones (that’s what she likes to be called, in a vain attempt to give her a personality) and Travis fail to see how this untruth could lead to actual problems. “It’s just words,” Derrick says, stupidly. “So how bad can it be?”

Well, it seems Naomi and Beau actually did go to a bedroom together (Derrick saw them), but she was too drunk and quickly passed out. Once the rumor goes around that they had sex, though, she wonders if perhaps Beau raped her and she just doesn’t remember — a nagging doubt fostered by Beau’s initial reluctance to let his friends believe he DIDN’T score with her (you know how guys are).

Soon, Beau is arrested on rape charges, and Jones is finding that Derrick may have had ulterior motives in choosing Naomi to start the rumor about. There’s plenty of drinking in this movie, all of which exacerbates the myriad problems and prevents anyone from doing anything sensible about them. And all along, everyone seems surprised that a rumor as simple as “two people had sex” could have led to so many wacky hijinks.

Most of the film is at least entertaining in a “this movie is dumb” kind of way. It has a cool alternative-techno soundtrack, which often drowns out the stupid things being said. And it’s nothing if not stylish. (In fact, it’s nothing BUT stylish).

But then we get to the final five minutes, in which we witness a sequence of events that might be the worst ending in film history. That’s where all bets are off, all hopes of redemption are gone. That’s where “Gossip” goes from being just a lame, worthless film to being a vigorously stupid piece of work that will infuriate anyone who sat through the previous 85 minutes of it.

D (; R, scattered profanities, sexual situations, fairly mild violence.)