|Most people with peanut allergies this bad would die. Yet, there's this.|
At school, Lisa is being made fun of by Sherri and Terri for having a big butt. A talk with Homer only convinces Lisa that her big butt is because she's fat. At the same time, Bart arrives to state that he got a 100% on a state capitals test, which is eventually confirmed by Mrs. Krabappel herself (because she left a map open for the class to see). As promised, Marge holds an impromptu party for Bart, but its pretty lame and features mostly relatives, as well as Ralph and Martin. Marge tries to salvage the party the best she can, but after implying Lisa likes getting fat, Marge runs off to console her, and the party abruptly ends.
Marge is unable to have fun with either kid, with Lisa's newfound struggles toward thinness and Bart's desire to stay away from Marge. She goes to the park, where she finds Nelson Muntz trying to grab tadpoles for food. Out of pity I guess, she gives Nelson Lisa's lunch, Lisa unwilling to eat right now. Later, after Bart and Lisa both turn down the opportunity to go to the bowling alley with Marge, Marge finds Nelson again and the two have fun bowling. Its here that Marge learns that Nelson's father has been missing for some time, having disappeared after leaving to get cigarettes. Out of pity, probably, Marge decides to have Nelson do some chores for the day for money. That night, though, Nelson's mom confronts Marge over giving Nelson 'charity', and the two get into an argument. Later that night, Nelson somberly walks to the Simpson house, and tells Marge that his mother ditched him to get an acting job in Hollywood. With nowhere else to go, Marge lets Nelson stay in Bart's room.
Though Bart can't really handle this new situation, Marge can't help but appreciate Nelson's charms. One night, though, Bart overhears Nelson in the living room, singing a song about his missing father. Bart then checks in on Lisa in the kitchen, whose dedicated efforts to lose weight go haywire when she goes on a crazed cake binge. As Bart leaves, Nelson finishes his song and talks to Lisa. He agrees to help Lisa with mean old Sherri and Terri, setting up a plot the next day to have the twins get hit with a skunk so Lisa can lead a mocking cry against them. With the mission complete, Lisa and Nelson return home to find Nelson's father. The man explains that he did go to buy cigarettes one day, but haphazardly goes to eat a candy bar full of peanuts, which he's allergic to. His face swelling, Nelson's father goes nuts (sorry for the pun) and runs into the street. The crazed man stumbles on a circus parade, whose ringleader practically captures the elder Muntz into the freak show, with people throwing peanuts at him to keep his disfigured, crazed form. That's where Bart finds and rescues the man, and now he's back to provide for Nelson once again, as well as his mom who found an acting gig. The Muntz family is back together, and everything seems okay though Homer can't get Lisa to conclude her weight problem sidestory.
The disappearance of Nelson's father, last seen in Season 9, became a little-used running gag, featured in a few episodes in recent seasons, but comes to a conclusion with this episode. This episode also features several occurrences of something that's popped up in recent seasons I've come to rather dislike: Nelson haw-hawing something but then immediately explaining why he's doing it, as though the audience isn't able to figure it out on its own.
That, combined with the rather farfetched explanation of how Nelson's father disappeared hurt this episode rather badly, making it one of the weaker entries in the entire series.
Final Score: 5.6