Arnold attempts to do everything on the legendary "List for a Kid's Perfect Saturday", but all of his plans go horribly wrong.
It is Friday and school is out. The students talk about what they want to do over the weekend. Sid wants to watch cartoons, Park wants to go to the park to play catch, Harold wants to go biking ... and what about Arnold? Arnold wants to do everything! In fact, he plans to do everything that's on the legendary list, handed down from kid to kid for generations. Until now no kid has managed to do that. Gerald then speaks aloud the tasks on Arnold's list in front of their classmates in the style of a televangelist:
to watch every cartoon from six o'clock in the morning until "Dance Craze,"
to eat three bowls of Sugar Chunks cereal,
to bike down the steepest hill in the city,
to play catch with every kid in the park
to go the movies and sit through it three times in a row.
Arnold is indeed willing to do it all. But he's not lucky at all: his alarm clock breaks when it falls off the table at night, so that he doesn't awake until 6:45. Hastily, he puts on his clothes and runs into the kitchen to eat his cereal. Unfortunately, they out of Sugar Chunks, so Arnold has to eat Prune Bran instead. As if this was not bad enough, the milk is sour. Arnold is disappointed and goes into the living room to move on to watching cartoons until noon, but only after a few seconds the TV set implodes because Grandpa has confused the voltages at the fuse box.
Just when Arnold is about to leave the house, several men block the door attempting to carry a piano through the front door while Grandma is ordering them around. Arnold climbs out of the window and goes to the park in order to play catch. He asks a boy named Steve to play with him but unfortunately the boy steals his ball. Being discouraged, Arnold takes his bike while Grandma is still trying to get the piano into the house, this time through a window on the first floor. When Arnold arrives at the highest hill of the city he is in high spirits again — until his bike gets stuck in wet tar.
Now there is only one task left on the list: Go to the movie theater and sit through three movies in a row. Of course that doesn't work out either because Arnold finds that he has a hole in his pocket; all his money must have fallen out of it after he got off his bike. The woman at the box office ignores his begging and so Arnold sneaks in to see Mud Man's Revenge II. But instead of the auditorium he enters right behind the silver screen. When he eventually manages to get a seat, the film tears and the theater's closed for the rest of the day.
Feeling miserable, Arnold heads to the boarding house's roof as the sun sets and throws the list away as the piano is being lifted onto the roof with Grandma on it. When Arnold tells Grandma he had a lousy day where nothing went right, Grandma decides to cheer him up by playing a song about not letting life get you down. As she plays, a clown van crashes sending dozens of balloons into the air. This helps Arnold feel better, and deciding to enjoy what's left of the day, joins Grandma in an encore with his harmonica.