Professor Brainard (Fred MacMurray) is a really absent-minded man who teaches chemistry at Medfield College. He invents a substance which gains more energy by striking different surfaces that he calls Flubber (flying rubber). He’s so excited about his discovery that he once again misses his own wedding to Betsy Carlisle (Nancy Olson). Naturally upset, she starts seeing another professor. To further complicate his life, he fails basketball star Biff Hawk (Tommy Kirk), and ruthless banker Alonzo P. Hawk (Keenan Winn) plots to steal the formula for Flubber. While all this is going on, Professor Brainard is trying to get the government and other backers to take an interest in his invention. He stages a demonstration but talks so much his audience drifts away before they see what Flubber can really do. More successful attempts to use Flubber result when the Professor puts Flubber into his car to make it fly, the basketball team employing it during a game, and Brainard himself using it at a school dance, and Alonzo P. Hawk who is finally brought down by the team. Finally Brainard’s problems start to turn around.