Hey Arnold!

Mr. Hyuhn, Ernie Oskar combine their resources to purchase a racing horse. But when the thoroughbred arrives, it turns out to be a dumb old mule./When Rhonda's dad buys her mother a fur coat for her birthday, the temptation is too great and Rhonda wears it to school.

Harold, Stinky and Sid steal rockets out of the science lab at school and set them off outside of an old Police Station./The deli shop where Mr. Hyunh works has a new owner and he's looking for a new head chef whose a real family man. Mr. Hyunh is a candidate. But so is his co-worker who has a very large family.

Grandpa enters his packard in the classic car competition. It is admired by all until someone admires it enough to steal it. Arnold and Grandpa take the law into their own hands and become private investigators to track down the thief./Phoebe is set to receive an award for her perfect attendance.

Mr. Simmons wins The Teacher of the Year award and The Knowledge Channel wants to do a documentary called "The Day In The Life of a Classroom", capturing the spontaneous moments in his class./Big Bob has a change of heart when he has what appears to be a heart attack and during his unconsciousness sees what a jerk he has been.

Rhonda uses her origami marriage predictor to tell who will marry who within the gang. Everyone becomes curious. Except Arnold who refuses to take the test, until Rhonda peeks his curiosity by telling him that it might predict that he will marry Lila. But Arnold is sorely disappointed when it predicts that he is going to marry Helga. Of course, Helga is ecstatic.

When Gerald tries to get rid of his little sister Timberly, Arnold sticks up for her by persuading Gerald to let her hang out with them. /Mr. Leichliter, the theater critic, posts auditions for his rendition of the classic play, "Eugene, Eugene". All the gang are up for the tryouts. Eugene wins the leading role of the hero.

It's April Fools and Helga has targeted Arnold as her practical joke victim for the day. When Helga goes one prank too far, Arnold stages a retaliation and brings in Grandpa's prized practical joke, a gift box that contains a secret surprise for its victim. The surprise turns out to be a bright flash that temporarily blinds Helga.

On the anniversary of his parent's disappearance, Arnold decides to give up hoping that they will ever return home. But while packing away their keepsakes in the attic, Arnold finds his father's old journal. The journal chronicles his parents' lives from the moment they first met deep in a South American jungle to the day they disappeared.