Arnold has a really bad day - the city is suffering from a heatwave, and whatever he does, Arnold just can't seem to get cool.

Arnold attempts to do something that no other kid has done before - completing the entire list of a kid's perfect Saturday! But, unfortunately, things don't go quite to plan.

Arnold and Helga must care for an egg for a school project about parenting. Meanwhile, Rhonda and Harold are project partners and must also take care of an egg.

Olga gets into a "Big Sis" program, but her "Lil' Sis" is Lila.

Helga gets amnesia, and Arnold starts acting nice to her.

When Arnold's pigeon gets sick, he takes it to "Pigeon Man", a person surrounded by pigeons who lives in a rooftop.

While Helga tries to find the perfect gift for Arnold, Arnold tries to find Mr Hyunh's long-lost daughter.

Arnold finds out Iggy wears bunny pajamas with feet in them, and Arnold accidentially spills the beans to Sid and Stinky, ruining Iggy's cool image.

Arnold's hat lands on the stoop of "Stoop Kid," - a bully who has lived his whole life on his stoop, and is highly protective of it. But, when it's Arnold's fault that Stoop Kid becomes the joke of the city, he must help Stoop Kid face his biggest fear - leaving his stoop for the first time.

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.

Arnold is asked by his Grandma to help save an old building, and then asked by Ernie to help knock the building down! Who will Arnold decide to go along with? How can he get out of this tricky situation?

While feeling the effects of laughing gas, Helga leaves a confessional message of love on Arnold's phone machine. She then has to get into the boarding house in order to erase the message.

When Helga loses her pink book, full of love poems about Arnold on the bus, it ends up in Arnold's hands. Now Helga must get it back before Arnold figures out who wrote the poems.

Helga is annoyed when Rhonda doesn't invite her to her slumber party - everybody assumes that "girly" parties aren't Helga's style. So, Helga is determined to prove her wrong, and gets a makeover.

Oskar gets kicked out of Suzie's room when they get into an argument, so Arnold tries to get them back together when Oskar moves into Arnold's room.

Arnold has trouble with the basketball coach and his favored son.

Arnold and the gang set out on a quest to find the hidden treasure of the mysterious "Wheezin' Ed" on Elk Island.

Arnold is given the assignment to tutor Torvald, the meanest, toughest kid in Arnold's math class, for the big math test on Friday.

On Valentine's Day, Arnold manages to arrange two dates; one with Ruth, the sixth grader he likes, and one with his French penpal Cecile (actually, it's Helga in disguise) – only for the real Cecile to suddenly appear and Arnold to discover what Ruth is really like.

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

When Bob has to go to a business meeting, Miriam and Helga are forced to go on the family road trip by themselves.

Harold is invited to Rhonda's party and befriends the female bully, Big Patty.

As a science assignment, Arnold and Helga have to work together, and get along with each other, for 24 hours in the Sunset Arms greenhouse.

The school is doing the play "Romeo and Juliet". Arnold lands the role as Romeo so Helga will do anything to beat out other girls to get the part of Juliet, so that she can kiss Arnold in the final scene.

Arnold's bland country cousin, Arnie, comes to visit. Arnold begins to notice that Arnie and Lila show interest in each other, making him jealous.