Tommy Callahan III (Chris Farley) is the loser son of 'Big Tom' Callahan (Brian Dennehy) who owns an auto parts company. After 'Big Tom' announces that he is engaged to be married to Beverly Barish-Burns (Bo Derek) and that Tommy is to have a step-brother Paul (Rob Lowe), he unfortunately dies on his wedding day. Tommy soon learns that the bank has denied the company a loan to create a new brake pad division at the plant. Refusing to let his father's dream die he decides to give up his inheritance as collateral, while heading out on the road with Richard Hayden (David Spade), his father old assistant, to try and win business. While Tommy's uncouth behavior turns away some people he has a knack for sales, and soon manages to raise the money necessary to save his father's business. Unfortunately his father's fiancee and would be stepbrother have other plans and Tommy and Richard must try to outwit them in order to win the day.