If you don't like the tone of "Diary of a Mad Black Woman," just wait five minutes and it will change. It is, at various times, a soap opera, a madcap farce, a melodrama, a crime drama and a Christian missionary tract. A film that can shift gears like that so often, and do it successfully, is a rare, surprising delight. Unfortunately, "Diary" does it painfully and awkwardly, displaying a blind ineptitude on the level of some of the worst films I've ever seen. It doesn't keep changing styles because of some grand master plan; it keeps changing because it doesn't know what it's doing. This movie is an absolute train wreck.

The main casualty in this horror show is Helen McCarter (Kimberly Elise), the wife of a prominent Atlanta lawyer named Charles (Steve Harris), who dumps her after 18 years of marriage so that he can be with his long-time mistress and their children instead. Charles is cruel and monstrous to an absurd, implausible degree, literally dragging Helen out of the house with no notice and coldly denying her any alimony, despite being filthy rich himself.

Helen finds solace in the home of her great-aunt Madea, and that's when the film turns into a badly handled, over-the-top farce. You see, Madea is one of those enormous, sassy, fast-talking old black ladies you see in movies, and she is played (as they so often are, for some reason), by a man in drag. He is Tyler Perry, writer of the stage play on which the film is based, and also the portrayer of Madea's vulgar brother Joe and Helen's cousin Brian. But Madea is clearly Perry's bread-and-butter, his Hamlet, his Mona Lisa. I see on Perry's Web site that the character has been spun-off into other plays in which she takes center stage.

Pity, then, that she's such a broad, unbelievable, hastily assembled character -- or at least she is in the film (which was directed by first-timer Darren Grant but adapted by Perry). She carries a pistol and encourages Helen to go back to Charles' house and tear up the place. She is meant to be "outrageous," but I don't believe anything she does. She doesn't belong in what is otherwise a dramatic comedy built around real emotions and relationships. She belongs in an "In Living Color" sketch, if anywhere.

But the film has more problems than that. If we were talking about one out-of-place character, that would be one thing. A movie can recover from a problem of that nature. But let's continue. Charles, it turns out, used to be involved in some nefarious deeds with low-lifes, and one of them blackmails him into being his defense attorney in an upcoming case. Then Charles is shot and becomes paralyzed (!), at which point Helen must work through her feelings of hatred for him and consider helping him, since she is still legally his wife. Unfortunately, she has already met and fallen in love with a hunky man named Orlando (Shemar Moore).

Meanwhile, Helen's cousin Brian has a wife named Debrah (Tamara Taylor, and yes, "Debrah" is misspelled like that), and she has a bit of a crack problem, and I think she lives on the street. For some reason, the movie believes that after all the mess with Helen and Charles and Madea and Orlando, we're STILL going to have room to care about ANOTHER story. To make the Brian/Debrah situation even more convoluted, Debrah doesn't want their daughter to join the church choir because it was music that got her (Debrah) on drugs in the first place. She doesn't say whether it was a church choir specifically that did it, but I like to think it was, because the image of pious altos and sopranos in choir robes passing syringes back and forth in the choir loft makes me laugh. But anyway: What the F, movie? Seriously, what the F?

After what feels like an eternity, the movie finally gets around to its hollow redemptions and trite messages, but darned if I care. The stories are illogical, the characters are badly written, and the film constantly wavers between being ludicrous and simply boring. The whole thing is a mistake from start to finish.

Grade: F

Rated PG-13, a little profanity, some vulgarity

1 hr., 55 min.