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.
Arnold hits Harold with a baseball, so Harold promises Arnold that he'll beat him the next day.
Arnold has a magic show and he makes a disappearing act and uses Helga as the person disappearing. Helga decides to play a trick and literally disappears. She bumps into a pole and has a dream on how the world would have been if she's gone.
The kids try to get in the book of world records so much that they would do anything, including most people on a one-person bike and the longest game of Crack-The-Whip.
Eugene is accused of pulling the fire alarm. In the school court, the jury thinks Eugene is guilty except for Arnold, who believes there is a shadow of a doubt.
Arnold loses Grandpa's watch inside the sewers, so he must retrieve from The Sewer King.
Arnold must find a way to recover his pig pet Abner after he runs away.
Arnold and Gerald must turn off all the lights in the city if they want to see Sally's Comet.
Helga decides to give her talented sister Olga a taste of reality by changing her grade in her report card.
When Arnold's pigeon gets sick, he takes it to "Pigeon Man", a person surrounded by pigeons who lives in a rooftop.
Arnold and Helga compete on a Spelling Bee contest.
Gerald goes to Arnold's place to meet the other residents.
Arnold is given the assignment to tutor Torvald, the meanest, toughest kid in Arnold's math class, for the big math test on Friday.
Arnold and the gang set out on a quest to find the hidden treasure of the mysterious "Wheezin' Ed" on Elk Island.
Arnold and the gang have no choice but to take the subway home after dark.
An older cool guy befriends Arnold, but Arnold realizes that he is really a shoplifter.
Arnold has trouble with the basketball coach and his favored son.
While Helga tries to find the perfect gift for Arnold, Arnold tries to find Mr Hyunh's long-lost daughter.
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.
All of the boarders get very curious to what is inside the very personal Mr. Smith's package.
Grandpa, Arnold, and Gerald are all going on an old fashioned camping trip... until Big Bob, Helga, and Phoebe show up with luxurious camping equipment.
When Arnold gets mugged in the street, Grandma teaches him how to defend himself, but the training and fighting starts to get to his head.
When the kids complain of being bored, Grandpa tells the story of the Haunted Train. So, the kids decide to go and see if the train exists for themselves.
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 friends decide to clear out a vacant lot to play baseball on, but the adults take over it, and use it for their own reasons.
At the Annual Cheese Fair, Helga tries her best to keep Arnold well away from Ruth - a girl who Arnold has a crush on.
Snow hits the city and Arnold can't wait to get out and have some fun... but wait, there's chores to be done... and when there done Arnold has the time of his life playing Hockey with the "crew."
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's favorite baseball player is playing his last game, so he decides to go and see his last game. The only problem is that he winds up with terrible seats.
Two girls from the sixth grade who are tired of the way that their boyfriends treat them, decide to take Arnold and Gerald to the school dance, but only to make their boyfriends jealous.
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?
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.
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.
An obsessed Helga steals Arnold's hat to complete her shrine to Arnold, which is hidden in the back of her closet. But, she notices how miserable Arnold is without his hat, and decides to give it back to him.
The kids are really looking forward to their field trip to the aquarium - especially when they remember the scary Lock Jaw from their last trip. But, when they get there, they see that Lock Jaw isn't really that scary. Arnold notices how neglected the old turtle looks, and returns later with Grandma to set it free.
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.
When Arnold accidentally ruins Eugene's new bike, he takes Eugene out on a day of fun, thinking that "every geek deserves his day".
Not looking forward to performing in Helga's "The Four Food Groups" musical, Arnold and Gerald decide to take the bus a few stops too many, but end up stuck downtown.
