

Malcolm swiftly breaks into the house, whereupon he tackles with Lester and subdues him after John is shot, but at the cost of his disguise being dropped in front of Sherry and Trent. Lester eventually arrives on the scene, having tracked down Sherry, and soon puts her in danger. In his efforts to stop her re-entering the house, he instructs Nolan to lock her out, only for the dim-witted guard to lock out Malcolm by mistake. Matters soon become complicated when John discovers that the real Big Momma has returned home prematurely. His discovery is witnessed by Sherry, who confess to him that she had no idea what Lester was planning, and didn't report her key was stolen out of fear of being fired.

After attending a church service with them, where he compels in his disguise for Sherry to not hold any secrets, Malcolm finds the missing money in Trent's footlocker after returning home to a surprise birthday party for the real Big Momma. During this time, Malcolm bonds with Sherry and her ten-year-old son Trent, both in disguise and as himself – posing as Big Momma's handyman – but finds nothing to link her to the robbery, nor to the missing money's location. This includes him dealing with her lecherous boyfriend, assuming her occupation as a midwife, and attending self-defense classes led by dim-witted security guard Nolan, whom the agents are later forced to recruit when he stumbles onto their operation. To maintain his disguise as Big Momma, Malcolm is forced to maintain the real Big Momma's lifestyle. Malcolm takes advantage of this by posing as her in order to bring Sherry to her house to get her to confess to her involvement in the bank robbery.

Malcolm and John find themselves staking out the home of Sherry's estranged grandmother, Hattie Mae Pierce – an overweight, elderly African American woman, whom her friends affectionately call Big Momma – in Cartersville, Georgia, and soon find that she is about to leave for two weeks to visit her ill friend.

Malcolm and John learn that Lester may be seeking to find his ex-girlfriend, Sherry Pierce, an employee of the bank who is suspected of supplying him with a key to the vault, as the money that was stolen was never recovered. Undercover FBI agents, Malcolm Turner and John Maxwell, find themselves assigned by their bosses into tracking down escaped convict Lester Vesco, who was serving a life sentence for murder and the armed robbery of a bank.
