Professor Ned Brainard's discovery of Flubber has not quite brought him or his college the riches he thought. The Pentagon has declared his discovery to be top secret and the IRS has slapped him with a huge tax bill, even if he has yet to receive a cent. He thinks he may have found the solution in the form of "Flubbergas," (the "son" of Flubber) which can change the weather, by making it rain inside people's houses, as well as in one car, too, which causes Shelby Ashton's car to get into an accident with a police car. The professor did this action in revenge for Shelby's interfering with his wife Betsy. It also helps Medfield College's football team to win a game, but it also has one unfortunate side effect: It shatters glass, which eventually places Brainard on the lam. At home, his wife Betsy is jealous of the attention lavished on him by an old high school girlfriend. On trial, Ned's future seems hopeless, until a farmer shows the court that his crops grew extra large because of Ned's experiment, which the farmer names "Dry Rain", and the professor is acquitted.