Catherine Boyd (Meg Ryan) is a highly intelligent doctoral student at Princeton University and is engaged to stuffy Professor James Moreland (Stephen Fry). Ed Walters (Tim Robbins), a mechanic and all-around regular guy, falls for Catherine and searches for a way to impress her. Believing that the key to Catherine's heart is his IQ, Ed passes himself off as a physicist with the help of Catherine's uncle, who just happens to be Albert Einstein (Walter Matthau).