FBI agent Malcolm Turner and his 17-year-old son, Trent, go undercover at an all-girls performing arts school after Trent witnesses a murder. Posing as Big Momma and Charmaine, they must find the murderer before he finds them.

FBI agent Malcolm Turner goes back undercover as Big Momma, a slick-talking, slam-dunking Southern granny with attitude to spare! Now this granny must play nanny to three dysfunctional upper class kids in order to spy on their computer hacked dad.

When a street-smart FBI agent is sent to Georgia to protect a beautiful single mother and her son from an escaped convict, he is forced to impersonate a crass Southern granny known as Big Momma in order to remain incognito.