Postman Butters delivers flyers for a new sushi restaurant in town. He delivers a flyer to City Wok, and the owner is less than delighted to find out there is Asian competition in town. The City Wok owner finds out that City Sushi has opened up right next door. The City Wok owner goes into City Sushi and gets into a fight with the owner. Butters is accused of causing an Asian turf war and the police take him home. His parents decide their son might have mental problems and they take him to a therapist where he is diagnosed with multiple personality disorder. The doctor prescribes lots of tender loving heavy medication. The news reports on the opening of the sushi restaurant in the Asian part of town now called "Little Tokyo", much to the anger of the City Wok owner and they start another fight. At the Stotch residence, Butters' parents think the medication isn't working; while Butters is only outside simply playing pretend, like any normal child. The Chinese guy comes to City Sushi and suggests they need a "tweaty." They eventually come to an understanding and agree to hold an assembly at the school, where they can teach the children about their cultural differences. Of course the City Wok owner has an ulterior motive. Butters is being interviewed by his therapist; the shrink wants to talk with Butters different personalities. He tells Butters that some of his personalities are going to try to kill him. But it really turns out that it is his therapist who is the one with multiple personality disorder.
As his therapist suggested, Butters has recorded himself sleeping. He reviews the recording and see his therapist come into his room, piss on him and beat him up. At South Park Elementary the presentation on Asian Diversity begins. The City Wok and City Sushi owners start the show, but the City Wok owner starts steering the show toward exposing the horrors of the Japanese. Butters goes to see his therapist and Butters tells him what he's caught on video. Immediately his therapist switches personalities and takes Butters with him on a jewelry heist. The therapist's personality switches back and he finds Butters trying to break into a safe. The therapist calls the police. No one is arrested, but Butters' parents promise to "ground the shit out of him." At City Sushi, the City Wok owner admits to being sneaky. He really wants them to have an Asian Diversity Festival together. The City Sushi owner agrees against his better judgment. Of course, the City Wok owner still has an ulterior motive. Butters is in his backyard burning the clothes he uses for playing his different characters, when his therapist's Billy personality chases him down, asking for help from Inspector Butters. The Billy personality wants Butters to help convince the therapist that their mean personality is scheming to take over completely.
South Park's Little Tokyo holds their Asian Diversity Day. The City Wok owner has built a "Tower of Peace" between the two restaurants. The City Wok owner invites the City Sushi owner to join him at the top of the tower. Meanwhile, Inspector Butters and Billy are going through the therapist's house. Suddenly Butters finds himself on the runs from the therapist's various personalities. But the therapist's most diabolical personality is finally revealed, that of the City Wok owner. The City Wok owner realizes he is late for his appointment, to meet the City Sushi owner at the top of the tower. He makes it up to the top of the tower, where he tries to make the City Sushi owner kill himself. The plan is foiled, when Inspector Butters and the police arrive. At least is it almost foiled, the City Sushi owner commits hari-kiri (or seppuku) when he realizes that he couldn't identify that the City Wok owner was really a white guy. He leaps from the tower and crashes into the top of his restaurant destroying it. At the Park County Police Station everything gets explained to Butters parents. Butters is glad that the therapist can now get the help he needs. The police decide differently, who needs another therapist, with no competition to drive him insane, they plan on releasing the therapist and letting him free to run City Wok, since he no longer has any competition to drive him insane. Of course the City Wok owner personality is certifiably insane.