An FBI agent Malcolm Turner is going deep undercover as he disguise himself as Sherry Pierces long-lost grandmother named Hattie Mae Pierce, aka Big Momma. And his latest assignment sends him to small-town Cartersville Georgia, where he is assigned to trap a brutal bank robber who they suspect will be coming down to visit his ex-girlfriend and her son, Trent. Now, Malcolm must somehow find a way to nab his criminal and the lady.