On its surface, the muddled new ''Guess Who" is a love story between Theresa (Zoë Saldana) and Simon (Ashton Kutcher). She is black. He is not. This is not important to them. But the movie needs something to do for 100 minutes, so it concocts a lot of harebrained physical comedy.
Theresa takes Simon home to suburban New Jersey to meet her parents, who are renewing their vows, and to announce their engagement. Her mother, Marilyn Jones (Judith Scott), is fine. It's her father, Percy (Bernie Mac), who takes the news as a betrayal.
He's so ashamed of his future son-in-law that he tells an underling at work that Theresa's boyfriend is a Howard-educated basketball player named Jamal. Yet Percy's love of the overwhelmingly white world of NASCAR is a fascinating paradox that the movie never calls him on. The framed photos of Jeff Gordon in his home are there chiefly as sight gags.
''Guess Who" might be an update of Stanley Kramer's well-intentioned 1967 ''Guess Who's Coming to Dinner." In that film, white Katharine Houghton brings black Sidney Poitier home to her white parents (Spencer Tracy and Katharine Hepburn). Tears are shed and lessons are imparted; sap and righteousness rule.
Nothing in the new movie's press notes mentions the old one. The races are reversed, and the sermons have been replaced with slapstick. This puts ''Guess Who" in closer company with ''Meet the Parents," as the clumsy, gangly, and inappropriate Kutcher does his shtick and the proud and unflappable Mac does his.
The movie will please those looking for easy physical comedy. Percy doesn't want Simon in his home, but after things don't work out with relocating him to a hotel, the disgruntled father sends the prospective son-in-law to his basement den and shares the foldout bed with him in case his little girl sneaks down for sex.
And those looking for extraneous plot entanglements will be thrilled to discover that the screenplay has plenty. For instance, when Simon quits his high-earning finance job and needs to borrow money, it's Percy who just happens to be a loan officer.
But if you're looking for a meaningful consideration of the intricacies that come with introducing your white boyfriend to your black family, you're probably eating nachos at the wrong multiplex. ''Guess Who" is glib in the same way that ''Meet the Parents" was.
We already know Percy is stubborn, but Mrs. Jones remains too preoccupied with learning the tango for their re-wedding ceremony to talk seriously with her daughter or to reason with her husband.
Ultimately, Percy doesn't care that Simon is white. He cares that Simon is a man who wants to take his daughter away. But since the movie begins as a comedy about race, it has to stay there. So just as Robert De Niro did to Jewish Ben Stiller, Mac taunts Kutcher into trouble, as in a scene where Simon is bullied into telling racist jokes at dinner.
It's like racial Russian roulette: Simon has to keep them coming until he inevitably crosses the line. The moment is interesting as a social experiment (how much racism can a person tolerate until he snaps?), but it's terrible as comedy: The Joneses look stupid cracking up at Simon's jokes, then getting mad at them.
Director Kevin Rodney Sullivan seems unsure about how to play all this. So he goes for a little of everything. There are moments of silly horseplay between Mac and Kutcher, ill-advised farce like that dinner sequence, and general embarrassment, such as when Theresa's randy slacker sister (Kellee Stewart) wants to know if ''it's true what they say" about white guys. Once in a while ''Guess Who" settles into a calm tone with such warmth and ease that it grows harder to tolerate the shenanigans.
Each of these warmer moments involves the story's women, especially Saldana, who steals the movie with her sharpness and exuberance, standing up to Mac and rolling her eyes at Kutcher. She's ravishing.
Watching ''Guess Who," I didn't always know what Theresa saw in Simon and why she tolerated her dad's parochialism. The only thing that truly makes sense here is what they see in her.
Wesley Morris can be reached at email@example.com.