Arnold and the gang must stop Big Bob from chopping down the oldest tree in town.

When the kids make their new teacher, Mr. Simmons, quit his job, the replacement makes them realize what they lost.

Helga drinks a potion to lose all feelings for Arnold.

Gerald's secret is revealed; he doesn't know how to ride a bike, so Arnold teaches him how.

Arnold and Gerald compete against Helga for the school newspaper.

When Harold is walking in the street, he finds a kitty that belongs to an old lady and he takes it, but then everybody appears, and Harold has to surrender the kitty to the old lady.

Schoolyard tradition has it that on the first Monday of June each year, the fifth graders throw the fourth graders into trash cans. So, Arnold and Gerald try to make a run for it. As more people are thrown into trash cans and the fifth graders know all the routes, Arnold and Gerald find out eluding the fifth graders is harder that they thought.

After Arnold accidentally kills Eugene's fish with a yo-yo, he must do something to make up for it.

An organ grinder's monkey kisses Helga, who's convinced she has caught 'monkeynucleosis'.

Arnold and Gerald do a spot of fishing, determined to catch the pond's biggest fish, the legendary "Big Caesar".

Gerald and Arnold get on the case when Timberly loses her Barney-esque doll.

The new girl is teased at school by Helga and the other girls, but she's soon accepted by everyone.

After Arnold saves Sid from an injury, Sid devotes himself to paying Arnold back with unending kindness.

Arnold and Gerald bunk off school, but their day is ruined by their fear of being found out.

Arnold and Gerald go around the city following "Porkpie", a mysterious man caught on film. They suspect, because of the clues, that Porkpie are planning to kill "Marty", who turns out to be Mr. Green.

In this variation of "The Tell-Tale Heart", Phoebe plagiarizes from a poetry book and uses one of the poems as her entry in a poetry contest. She wins, with her prize being a trophy resembling poet Emily Dickinson. Then, the trophy haunts Phoebe into confessing.

Wolfgang and his gang of fifth graders challenge Arnold and his friends to a football game, but he has to first persuade them that his plays are good enough for them to win.

Gerald, getting tired of his family bugging him, moves out of his home and into Arnold's boarding house, only to realize emancipation is not all it is cracked up to be.

Gerald becomes an entrepreneur out of selling watches until the market becomes saturated.

Rhonda and Nadine fall out over working on a project at school, leaving Arnold to work with both of them separately.

Arnold and Gerald send the neighborhood alien crazy as they broadcast a mock Halloween radio show.

Arnold's Grandpa enters a Chinese Checkers tournament to reclaim his pride lost forty years ago. Robby Fisher's name is a parody of Bobby Fischer.

Helga's mother tries to let her and her father, Bob, bond.

Arnold follows in his Grandpa's footsteps and competes in the annual block party eating contest. After much munching Old Football Head goes stomach to stomach with eating legend Seymour 'The Disposal'.

Rhonda gets glasses and finds out what it is like to be a "Geek".

Helga uses Stinky as her boyfriend to try to make Arnold jealous.

Arnold develops a crush on Miss Felter, a substitute teacher, thinking he is having dinner at her house, only to realize that the one she invited was her fiance, whose name is also Arnold.

Phoebe becomes hall monitor and asks Helga for tips. She becomes overwhelmed by the "power" and soon everyone wants the old Phoebe back, even Helga once she realizes Phoebe's also giving her detentions.

Harold runs away from his Bar Mitzvah, thinking he will retain his childhood this way.

Arnold and his friends get Coach Wittenberg to be their new bowling coach.

The ghost of a former boarding house resident is believed to have been causing strange occurrences in there when Arnold and Gerald find an old pair of glasses believing to have belonged to him.

After finding out that his idol is a haughty, primped actor, Eugene sets out to become bad.

Helga and Arnold fall asleep and have their own "parody/dream" of the opera Carmen.

Arnold and a descendant of his grandpa's arch enemy, Rex Smythe-Higgins, compete in a boat race.

Teachers of Arnold's school go on strike because of inadequate funding; He and his friends are on cloud nine, only to find out that every lost school day will be taken from their summer vacation.

After creating an idea for a parade float, Arnold is confident of it showing up in a parade.

A lounge singer moves into the Sunset Arms after renouncing his songwriter, who also moves there.