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

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

Eugene gets the lead role in the school musical "Eugene, Eugene". But the play director cuts the parts that Eugene is a hero, and makes the parts look like he is a loser.

Gerald's Ghost Bride story inspires the other boys to venture into the cemetery at night, but they may have bit off more than they could chew, because they're hunted down by two different Ghost Brides.

The kids must face two bullies when a new kid, Ludwig, returns and wants the vacant lot for himself.

Arnold finds a journal describing the adventures of his parents in the Jungle. Also, it contains a map telling where they had to go after they left him.

Arnold finds a journal describing the adventures of his parents in the Jungle. Also, it contains a map telling where they had to go after they left him.

Arnold does something for Timberly, causing Timberly to have a crush on Arnold. She makes Lila start to like Arnold because he has been helping Timberly.

When Arnold, the boarders and the Patakis go to the beach, a girl uses Arnold to win a sandcastle competition. Ernie gets buried in the sand. Miriam and Suzie start taking dancing lessons. Grandpa thinks he's stuck on an island. Oscar starts using a metal detector to find ""treasure."" Big Bob gets a bad sunburn. Helga tries to warn Arnold that he's just being used.

Sid becomes obsessed with cleanliness.

Helga and Harold must return to town on their own after the bus leaves them behind after a school trip to a chocolate factory, and Helga has tickets for a wrestling match and she can't be late.

When Arnold gives the superhero Monkeyman a taste of normal life, he's far too busy to bother helping the weak and downtrodden.

Arnold, Sid and Gerald find a bag filled with money, but when Arnold loses it, everyone thinks he stole it.

Ernie starts dating a tall model, but she doesn't want to continue dating him because of his height.

Helga inscribes her name in her Arnold locket.

When Mr. Simmons is upset that Principal Wartz is being too strict with the students, Wartz decides to resign and he selects Mr. Simmons to take his place. The newly promoted Principal Simmons decides to make massive reforms to permit the school environment to be more liberal, though will the students at P.S. 118 appreciate his authority?

Harold is suspended and will do anything to get back into school.

Helga decides to act like Lila so Arnold will like her..

Arnold gets stuck in a tree with Harold and Eugene.

Arnold visits his cousin Arnie, whose friends look remarkably familiar to Anrold's

Mr. Green runs for city council.

Sid thinks Stinky is a vampire.

When Phoebe breaks a leg after being hit by a truck, Helga believes it's her fault (and it is), so she starts being nice to Phoebe. Yet when Phoebe's leg heals, she decides to stay disabled for a little longer.

Arnold asks Grandpa what really happened with his parents, and he finds out that they disappeared after they left the country on a plane, although they might still be alive.

After Arnold saves the life of a rich man, the man invites Arnold and Grandpa Phil to his house. He tells Arnold that he wishes Arnold was the son he never had, but he really does have a son, but they share nothing in common.