On its face, "The Heat" looks like a warmed-over hash of stale movie formulas. While the film is true to the conventions of the odd-couple/buddy-cop comedy, its stars infuse the formula with surprising energy and a surpassing sense of fun.
Sandra Bullock has never been funnier as Ashburn, an uptight, conceited FBI agent who is great at cracking cases, but terrible at working with others. Her personal life is a disaster — her most satisfying relationship appears to be with a neighbor's cat. Ashburn is bucking for promotion, but her boss is wary of putting her in charge of other people because she's so widely disliked.
Ashburn is sent to Boston to crack a case involving a mysterious drug lord who controls narcotics traffic in the city, but is unknown to law enforcement. There she meets Shannon Mullins (Melissa McCarthy), a bullying, brash city detective who is feared and hated by her squad, from the captain on down to the officer who runs the holding cell.
Mullins and Ashburn appear to be the only women in their law enforcement circles, but in Katie Dippold's excellent script, their isolation is largely self-imposed by their personality problems. Each needs to dominate every situation, and each is convinced that they are the best. Naturally, they are repulsed by each other. Mullins can't abide Ashburn's prudish corporate style, while Ashburn is disgusted by Mullins' profanity and violent streak. Despite their misgivings, they are ordered to work together, rattling cages in the Boston underworld to see if they can shake loose the identity of their target.
Cop comedies have varying standards of plausibility, from the faintly believable ("48 Hours") to the willfully ludicrous (the movie reboot of "Starsky and Hutch"). "The Heat" isn't a credible crime movie, but neither is the plot so off-the-rails ridiculous as to distract from the comedy chemistry that develops between Mullins and Ashburn. A few set pieces drag on a little long, like a scene in a bar where the two bond over what appears to be about a gallon of whiskey, or an undercover operation in a nightclub to wiretap the cellphone of a drug lieutenant.
The leads are backed up by an excellent supporting cast. Dan Bakkedahl is hilarious as a sputtering albino DEA agent whom Ashburn and Mullins suspect might be in league with the drug dealers. Michael Rapaport is great as Jason Mullins, the detective's ex-con brother who might have a line on the identity of the bad guys. The entire Mullins family — a cranky, blue-collar Boston crew — is excellent. Jane Curtin is especially great, if underutilized, as the mother to the clan, with the best Boston accent in the group.
Director Paul Feig has a knack, shown in "Bridesmaids," for making movie comedy look like improv. Miss McCarthy is at home in this mode — her escalating rants seem to bubble up spontaneously from deep inside her. What's perhaps more surprising is that Miss Bullock seems just as capable of throwing her comedic weight around.