Mr. Burns and Smithers take a train back to Springfield after attending the annual Harvard-Yale football game. The train makes a brief stop because of a discarded couch on the tracks and a man named Larry comes up to the train and tries to hawk cheesy merchandise. He suddenly sees Mr. Burns, gasps and takes out an old picture of a man who looks similar and compares the two. Suddenly the train pulls away, leaving Larry behind, though he has time to ask the conductor where the train is headed. Meanwhile, the Simpson family are on their way home from visiting a cider mill and see Larry hitchhiking. After much discussion, the family turns around and picks up the hitchhiker, despite having already made it all the way back home. Larry asks the Simpson family about Mr. Burns, and after a brief explanation of their past grievances with the old man, drops Larry off at his mansion. Larry first receives a cold welcome from Burns, who thinks he's a door-to-door salesman, until he reveals that Mr Burns is his long-lost father.
Mr. Burns is at first shocked, but after acknowledging the resemblance admits that Larry was the product of a one-night stand with the daughter of a former flame at a college reunion. At first, Mr. Burns is overjoyed to have a son and tries to shape Larry after himself. Burns takes Larry to fancy parties for the rich and tries to have him enrolled in Yale, but Larry keeps acting like an oaf and proves to be an embarrassment. Larry is put to work in Sector 7G at Springfield Nuclear Power Plant alongside Homer and the two become fast friends. Larry invites Homer to dinner, and at dinner, Mr. Burns becomes frustrated due to Larry's boorishness and tells him that he wishes he had no son. Homer tries to convince Larry to fake a kidnapping so that Burns will admit that he loves his son, and although Larry at first opposes the idea, he eventually agrees to do it. After going through with the plan, Larry moves into the Simpsons' basement. Homer calls Mr. Burns and says that he can have Larry back if he admits that he loves him. Marge eventually discovers the plan and convinces Homer and Larry to abandon their plot, but as they leave the house they are spotted by a news helicopter and are chased by reporters and police.
The two are chased into a cinema where they climb out onto the marquee and have a brief standoff with the police. Homer gives a heartfelt speech to justify Larry's actions and Mr. Burns forgives them for the hoax, but explains he cannot be the family whom Larry needs. Larry says that is okay and announces that he has a wife and children back home who are probably worrying about him as he had only gone out a week ago for coffee. Burns and Larry say their goodbyes, with Burns musing on the fact there is another kidney out there for him. Larry announces that they should have a party and the episode ends with the people of Springfield dancing outside the movie theater, with music and drinks coming out from nowhere, all to the sound of Journey's "Any Way You Want It".