An FBI agent, Malcolm Turner (Martin Lawrence) is once again, turned into “Big Momma”, an older aged woman nanny. This time, though, it is because the FBI has found out that a software developer has developed a dangerous computer virus. Tom Fuller (Mark Moses), the software developer has made a computer virus that can enter US classified files, and wants to distribute it to terrorists around the world and make a pretty penny at the same time. To stop him, Turner must go undercover as a nanny to Leah Fuller (Emily Proctor), and her three demanding kids in order thwart Tom Fuller and his diabolical plan.