FBI agent Malcolm Turner (Martin Lawrence) is tough, smart and a master of disguise. There's nothing he can't handle. Stop a brutal crime ring? No problem. Malcolm transforms himself into an aged Asian man to crack the case. Malcolm's latest assignment brings him to a small southern town, where he's determined to trap a brutal bank robber (and recent prison escapee). Malcolm sets up a stakeout across from the home of a southern matriarch known as Big Momma, who's about to be visited by the con's former flame, Sherry (Nia Long), and her son (Jascha Washington). It's a simple plan, but there's one Big Problem: Big Momma has unexpectedly left town. So Malcolm, taking on his most challenging "role" ever, decides to impersonate the cantankerous Southern granny. Using a few tricks of disguise, he completely transforms himself into Big Momma, even taking on the corpulent septuagenarian's everyday routine - from cooking soul food to delivering babies to "testifying" at the local church. As if things weren't complicated enough, Malcolm finds himself falling for Sherry, who might be hiding some stolen cash. Now, Malcolm/Big Momma must somehow find a way to get his man - and woman.