21st Century Fox21st Century FoxThe Other Woman is a movie that’s almost exactly 50 times longer than it needs to be–its trailer gives away the whole story in about two and a half minutes. Not the you-go-girl empowerment at the end, of course–but that’s engraved in the film’s chick-flick DNA, and will come as a surprise only to those but recently born.

The movie has a light, jaunty comic rhythm, however, and it’s worth seeing to be reminded of how funny Leslie Mann can be. Mann is sometimes bad-mouthed as a free rider in hit movies directed or produced by her husband, Judd Apatow—Knocked Up and The 40-Year-Old Virgin among them. But she’s good in those pictures. And here, deploying her skittery chatterbox charm and slapstick chops as well, she's irresistable. Cameron Diaz and Sports Illustrated über-babe Kate Upton round out the film’s female ensemble, but Mann is the star.

She plays Kate King, a stay-at-home housewife married to a condescending dot-com hotshot named Mark (Nikolaj Coster-Waldau, of Game of Thrones). Kate knows nothing about Mark's business, apart from the fact that he occasionally wants her to sign mysterious documents she doesn’t understand. Nor does she know that on the side he's dating a sleek Manhattan lawyer named Carly (Diaz), who believes that he's single. Showing up at Mark’s house unannounced one day, Carly learns that he's not when Kate opens the door.

Carly is steamed—she was hoping Mark might be the guy she could finally settle down with. ("I’ve been dating for decades," she moans.) Kate, for her part, is completely unmoored by Mark's extensive infidelity: "You had sex with my husband 50 times?" she asks Carly. "Don’t you have a job? Hobbies?" Since the only "friends" Kate has are really Mark’s, she needs a confidante of her own in this dark hour. In desperation, she latches onto Carly, and soon they’re bonding over a shared affinity for tequila

Kate and Carly next learn that Mark has been cheating on both of them with a third woman, the 20-something Amber (Upton). It may seem crude to reduce Upton to her famously impressive physical assets, but director Nick Cassavetes is happy to ogle her at length as she jiggles down the beach in a minimal bikini. At one point, she's referred to simply as "the boobs." It's obvious that she's still new to this acting thing, but she comes across as a good sport, and that's all that's required here.

As the trailer blithely reveals, the three women band together in search of payback. Kate takes the lead, spiking Mark’s morning smoothies with sex-change hormones, among other amusing torments. Carly consults her father (Don Johnson) for instruction about financial scams, Amber hacks into Mark’s computer, and before long they've got the goods: along with his romantic betrayals, Mark has also been cheating his business associates. Soon the women are all off to the Bahamas, where he does his shady offshore banking.

As predictable as the movie’s conclusion is, the story has some original twists. (Kate's teary gin-guzzling as she watches her old wedding videos is a fresh take on the traditional drunk scene.) And the supporting cast—including Taylor Kinney as Kate's affable brother and Nicki Minaj as Carly's secretary (deploying a rich Queens honk)–bring added kick to the proceedings. The target audience for this picture–hello, ladies!–may well love it. But luckless guys dragged in against their will could be surprised—they might actually stay awake through it.