The cartoon phenomenon known as Hey Arnold! featured an ensemble cast that got up to all kinds of edutainment, and many of them will be returning for the Hey Arnold! Jungle Movie. But it's been 15 years since Hey Arnold! was last on the air, so even the most die hard fan should be forgiven for being a little hazy on the details of how Hey Arnold! ended. Of course, solving that mystery requires knowing what happened in the Hey Arnold! finale. Well, the answer is: a lot.
Though it wasn't the final episode to air, the final episode of the show produced was a two-parter called "The Journal," which was meant to lead into the Hey Arnold! Jungle Movie before the movie was scrapped. Hey Arnold! Jungle Movie was also preceded by a 2002 theatrical film called Hey Arnold! The Movie, which could also be seen as a finale of sorts, but none of the episodes of Season 5 — the last season — ever referenced or were affected by the events of the movie, despite some of them airing after it.
While re-watching the entire series is the only way to catch every reference that the Jungle Movie could make, consider this your refresher on the most relevant events in the fictional city of Hillwood. (Yes, the city has a name, and, no, it's not New York.)
It was the episode "Parents Day" that first tragically revealed that Arnold's parents disappeared on a humanitarian mission to Central America — the fictional country of San Lorenzo, to be specific. However, the plot of "The Journal" is kicked off on Oct. 5, the anniversary of the day his parents left, when Arnold finds the titular journal while packing his parents' things up in the attic. The journal belongs to his father, Miles, and it details how he met Arnold's mother, Stella, while in San Lorenzo and everything that led up to the disappearance.
Miles was part of an anthropological research party with his college friend, Eduardo. While in San Lorenzo, he met botanist and physician Stella, who soon becomes his regular physician considering how clumsy Miles is. The two fall in love, and, while hiking one day, they fall into a ravine from which they are rescued by one of the Green Eyed People — the indigenous inhabitants of San Lorenzo. To repay their savior, they track down a relic called La Corazón from La Sambra, a local river pirate who, Eduardo reveals, stole it from the Green Eyed People. Stella and Miles successfully recover it and return it to the Green Eyed People's ancient shrine.
In return, after they get married but before their honeymoon, they're given a wedding gift by the Green Eyed People: a piglet, who is currently Arnold's pet Abner.
Some time later, Eduardo asks them to return to San Lorenzo because the Green Eyed People have been struck by what Stella identifies as a sleeping sickness. The pair create a cure and drop it off at another shrine. Then, when Stella is about to give birth, Eduardo and Miles are cut off from the town by an erupting volcano. But, when they stumble on one of the Green Eyed People's temple, they find a bed has already been prepared for her there. Even crazier, the eruption stops the moment she gives birth to Arnold, causing Stella and Miles to identify him as a "miracle baby." Sadly, as Arnold grows, the dangers of the jungle make Stella and Miles realize San Lorenzo is no place to raise their child, so they return to Hillwood and move in with Miles' parents.
All is happy and bright until after Arnold's first birthday, when Eduardo comes calling at the boarding house. The Green-Eyed People are again succumbing to the sleeping sickness, and Stella and Miles are needed to help them. Heartbroken, they leave Arnold in the care of his grandparents and make what they believe will be a short trip to help the Green Eyes, who have helped them so much over the years. And it's from this trip that they never return.
Upon learning all of this, Arnold is at least happy that he got to learn more about his parents and why they left him, even if he doesn't know what happened to them next. But, on the last page of the journal, he finds a map that details the San Lorenzo route his parents took when they left that final time. Finally, after all these years, a clue that could help him answer the question that has been weighing on him since childhood.
Sadly, "The Journal" ended with a cliffhanger that was meant to lead into the cancelled Jungle Movie. Happily, now, after all these years, fans — and Arnold — will finally get to know what happened to his parents.