Following on from the plot of the last movie, babies can communicate with each other using 'baby talk', and have an innate knowledge of the secrets of the universe. The baby geniuses become involved in a scheme by media mogul Bill Biscane (Jon Voight). Helping the geniuses is a legendary superbaby named Kahuna. He joins up with several other babies in an attempt to stop Biscane, who intends to use a state-of-the-art satellite system to control the world's population.
Caesar is having a hard time dividing his time between his band and his rich girlfriend, Buffer. Buffer's dad doesn't like Ceasar for her. He called in Caesar to make a bet. If Caesar gets to make a hundred thousand dollars within six months, he can have Buffer but if he does not, he won't see her forever. How can Ceasar win the bet if what he only knows is jam with his band mates?