Kenny's dad receives a letter on the mail, his wife thinks it looks too fancy to be another bill, turns out he inherited a 20 million dollars share of some old Scottish lord named Shaverlegs McCormick, whose illegitimate grandson is said to live in South Park, Colorado.
Stuart who is in complete disbelief his grandparents weren't his biological ones, is picked off by a limo that takes him to Denver's airport and flies all the way to Scotland to take part in the funeral and the reading of the will; he is taking a lot of smack by the legitimate descendants of the dead McCormick, and is mostly ridiculed by these rich bastards about his poorness. Once he returns to America, Stuart decides to take good care of himself, he and his wife have a discussion whether the McCormicks should move to the Blacks' neighborhood, or should they remain in their current place of residence and build it from the ground up.
Kenny goes with his family to the South Park mall and buys some new clothes, afterwards they go to the video games store where Stuart buys them whatever they want, Cartman who's there with his mom begging her to buy him only one B-rate game near the counter is shocked and faints.
Stuart consults with Gerald, who becomes his business guide ("Come on, Gerald, everyone knows your people are good with money! Do me this one favor and help me to pick where to invest my money"), and decides to buy small parts in the ownership of several places in town: Pi Pi's Splashtown, City Wok, Tom's Rhinoplasty and Shady Acres, he gains more profits from these 4 and soon becomes the richest man in South Park.
Cartman is devastated being the poor kid at school and tries to kiss up to Kenny to get some of their fortune, but he's left behind by Kenny who goes playing football with Stan and Kyle, not caring about his dad's new wealth that much.
Stuart is adjusted to the good living, drinking pricey wine instrad of scotch and signing the contract over buying 95% of the Pizza Parlor he used to work in as a teenager, only to have the Police knocking on his door and announcing him that he wasn't the legal inheritor to the fortune he's using, as the widow of Devin McCormick (the guy who died in "Death"), who's the real illegitimate grandson of Shaverlegs McCormick, had claimed in the precinct and it's been verified by DNA (her son submitted a sample). Stuart is forced to evict his newly-built home, and come down to the station with them, to transfer all the money to her shared account.