Unemployed 28-year-old cartoonist Gordon "Gord" Brody leaves his parents' home in Portland, Oregon, to pursue his lifelong ambition of obtaining a contract for an animated television series. His parents give him a car in which he drives to Los Angeles and starts work at a cheese sandwich factory. Gord shows his drawings to Dave Davidson, the CEO of a major animation studio; Davidson tells him that the artwork is really good, but that the concepts depicted, including a vigilante "X-Ray Cat", are nonsensical. Disheartened, Gord quits his job and returns to his parents.
Gord's father Jim constantly insults and belittles him following his return, telling him to forget about being an animator and "get a job". When Gord pressures his friend Darren into skating on a wooden half-pipe he has built outside the Brody home, Darren falls and breaks his leg. At the hospital, Gord impersonates a doctor, delivers a baby, and meets an attractive nurse named Betty, who uses a wheelchair, has an obsessive penchant for fellatio, and wants to create a rocket-powered wheelchair. Gord lies to Jim that he has got a job and goes out to a restaurant with Betty, pretending he is at work. However, Jim sees him there, and also disparages Betty due to her disabilities. After a fight in the restaurant, Gord is arrested and bailed out by Betty. Following her advice, Gord attempts to continue drawing, however he gets into an argument with Jim, who then smashes Gord's half-pipe. Gord and his parents then go to a family therapy session, where Gord falsely accuses Jim of "fingering" Gord's younger brother, Freddy. The 25-year-old Freddy is sent to a home for sexually molested children while Gord's mother Julie leaves Jim, and ends up dating the basketball player Shaquille O'Neal. While in a drunken stupor, Jim tells Gord how much of a disappointment he is to him. Affected by Jim's words, Gord decides to abandon his aspirations to be a cartoonist and gets a job at a local sandwich shop.
After seeing a television news report on Betty's successful rocket-powered wheelchair, Gord is inspired to pursue his dreams once again. He returns to Hollywood with a concept based on his relationship with his father: an animated series called Zebras in America. Jim follows him there after threatening Darren into revealing where he had gone. While Gord is pitching the show to Davidson, Jim bursts in and trashes Davidson's office. Thinking Jim's actions are part of Gord's pitch, Davidson greenlights Zebras in America and gives Gord a million-dollar check. Gord spends a quarter of that money on an elaborate thank you to Betty for inspiring him, and the remainder to relocate the Brody house to Pakistan with his father inside, unconscious - a response to Jim's earlier put-down that "If this were Pakistan, you would have been sewing soccer balls when you were four years old!"
Gord and Jim soon come to terms, but are then abducted and held hostage. The kidnapping becomes a news item, as Gord's series has already become popular. After 18 months in captivity, Gord and Jim return to America, where a huge crowd, including Betty, welcomes them home.