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.

Harry Sanborn is an aged music industry exec with a fondness for younger women like Marin, his latest trophy girlfriend. Things get a little awkward when Harry suffers a heart attack at the home of Marin's mother, Erica. Left in the care of Erica and his doctor, a love triangle starts to take shape.