Having learned his lesson after the events of The Nutty Professor (1996), meek, gentle Dr Sherman Klump dedicates himself to science. However, when Denise Gaines, a beautiful fellow DNA researcher, enters the picture, once more, Dr Klump is in love. And, as the love-smitten professor dreams of a brighter future, the lean-and-mean Buddy Love persona emerges, demanding freedom. Now, the nasty alter-ego stands in the way of happiness, and poor Sherman must do everything in his power to rid himself of Buddy once and for all. Can the rowdy Klump family lend a helping hand?