Fred is experimenting with a giant chicken to try to get Harry back to normal size. Meanwhile Idella is jealous because Harry is spending a lot of time with a female fly. Idella flashes back to when Harry and her were young lovers and Harry was leaving for Vietnam. Idella is about to murder the fly when it flies into a window and dies. Idella and Harry make up at the end of the show and Fred disposes of the dead fly.

The Pratts, the Edisons' yuppie neighbours, stay at the mansion when they get their house renovated and make themselves a pain in the behind. Casey has hostile feelings towards them and dreams of experimenting on them, but Fred and Casey and too scared to kick them out. So Harry takes it into his own hands and scares them out of the house, but only Ike and Turner know what he did. Throughout the show Harry is carrying out conversations with ants.

The show starts with Tina politely telling her date that she doesn't really like him. Turner's tooth is loose, and Fred is out buying popcorn for the big movie ""Tara, Tara, Tara"", a TV remake of ""Gone with the Wind"". Fred misses most of the movie because he's putting Turner to sleep, but it turns out to be no great loss. Turner dreams that he's visited by the Sandman (a boring comedian), the tooth fairy (an Englishwoman) and Mr. Coffee (who is in the middle of a messy divorce). The show ends with a monologue by Uncle Harry.

A gangster boss just got out of prison so he sends his two stoolies to look for the guy who ratted on him, Harry Orca. Turner lets them into the house by mistake, and they hold the family hostage and almost kill Harry. Richard comes over to complain about an illegaly-parked car but he leaves without realizing that the family is in danger. When the gangsters can't bring themselves to kill Fred, Idella takes the matter into her own hands and chases them out of the mansion right into the arms of Richard Pratt and two policemen.

For Fred and Casey's 16th anniversary, Fred goes to the mall and gets her two tickets to see her old band-mate Jaz Pope. The family watches a video of Casey and Jaz to see what she was like. After Jaz' performance, which really stunk, Casey is debating whether or not to tell Jaz the truth about how bad her music is. Casey decides not to, and Fred, who Jaz thinks is Casey's old boyfriend Snake, doesn't help either. Jaz comes over to the mansion and she and Casey give a concert to the family.

The family is worried whether Uncle Lenny will make it to the mansion for Christmas because of a big storm that's predicted. Kiefer tells Turner that Santa Claus doesn't exist. Meanwhile Lenny's dogsled gets snowed in, he hitches a ride on a plane, falls off it and collapses in the snow. Turner goes to sleep asking Santa to forget about all the presents for him and to help his Uncle instead. Santa comes to Turner (in a dream?) and takes him to where Lenny is lying in the snow and they bring him home for Christmas.

Ike is being mean to Turner and Casey yells at him when he puts his man in the toaster so he goes up to his room to play with his dollhouse. Casey comes up to talk to him and they make up but Tina bursts in and yells at him about her tape. Idella reads a letter from Lenny to Casey. Turner is really upset and dreams about him being the boss. All his kids are bothering him so he learns how tough it is to be a parent. He apologizes to the family, and at the end of the show he is made King of the House for 44 minutes.

This episode is done live, in front of an audience in Toronto. Fred's too sick to go to the zoo but the family doesn't seem to mind. He gets depressed about this, collapses and dies and spends the rest of the show observing how the family responds to his death. The lights switch back and forth between Fred and the family and weird things keep happening. Then all the lights go out and the family comes back to find Fred lying on the floor. His death was just a dream. Needless to say, the cast is not happy with how the show turned out and Fred blames the whole thing on the producer.

Fred and Tina finally discover a way to get Harry and Turner back to normal. Turner doesn't really want to be small, Casey doesn't really want it either because Harry and Idella are going to move out. Turner and Harry are put in the chamber for the final time, but, as Ike points out, they forgot the ball. When the experiment is finished, the family takes one look at Turner and Harry and scream their guts out. The director yells ""cut"", the season ends, and the party starts. Everyone is different at the party: Idella talks with a Caribbean accent, Fred is a pompous baboon, Lenny is a boor, Turner is going to the desert with a biker gang, Harry is planning to do a fishing show, Casey is a total ditz who's going to do a show in Venezuela, Ike's voice is changing and Tina is overeating. Fred is thinking of leaving the show, but gets up to give a speech and breaks down. He decides never to leave because Maniac Mansion is his family. Everyone starts clapping, then Fred wakes up, and