Grossly overweight yet good-hearted professor Sherman Klump takes a special chemical that turns him into the slim but obnoxious Buddy Love. Sherman falls in love with Carla, a chemistry graduate student. However, his alter ego Buddy begins to take over and uses Sherman's work to impress a wealthy alumnus. Buddy's aggressive behavior and womanizing ways cause problems, and Sherman must fight to regain control of his body and prove himself to Carla and the others.

In Nutty Professor II: The Klumps, Professor Sherman Klump creates an alter ego named Buddy Love, who is confident, charming, and incredibly rude. While Buddy takes over Sherman's life, chaos ensues as Sherman tries to find a way to get rid of his alter ego. With hilarious slapstick comedy and outrageous situations, this movie takes a comedic look at the struggles of a brilliant yet overweight professor.