All Grown Up

All Grown Up is the second half of the fourth episode of the twenty-fifth season of, and it's also the series finale.

Summary
The gang finds a fortune telling game and gets a hint of what their futures might hold.

Plot
(NOTE: The orange text is the episode in a flashback 20 years later.)

After Arthur picks up a book from the library, he and Buster talk about how you don't always get what you expect, but sometimes what you don't expect proves to actually be pretty good. For example, Buster tries a lavender flavored chocolate made by Patrick, which he initially recoils at because it tastes like soap, but soon finds he likes it. Muffy tries to show off her new dress to Francine only for it to get covered in mud by a passing car; seeing an ad for a dress with a similar look on a bus, she decides that she's a trend-setter. While choosing players for a baseball game, Francine accidentally picks George due to a misunderstanding, but he ends up scoring a home run and winning the game for her team. Arthur suggests that sometimes the unexpected things are what's meant to be – only to discover that Ms. Turner accidentally gave him a book about drawing animals instead of the one he wanted.

Arthur, Muffy, Francine, and Buster head to the library so Arthur can exchange the book, but Ms. Turner is nowhere to be seen. Another patron informs them that she is in the stacks, so they go look for her, but instead find a hidden room full of stuff not in circulation. They accidentally turn on a fortune telling game called "Oskar the Oracle Octopus", which claims that it can tell their futures based on their personality traits. They decide to play it and see what they will be when they grow up. When told that she will become a public servant, Muffy imagines being a mail carrier, but her friends explain that she could become a politician instead. Francine's prediction is a businesswoman, which prompts her to imagine her harried older self-working in an office answering phone calls. Buster's prediction is that he will become a teacher, which his friends find laughable; his fantasy involves teaching a class where all the students are the Brain. Arthur attempts to get his prediction, but the game's batteries run out before it can state it.

The four kids then leave, but the patron from before stops Arthur and encourages him to take the book that Ms. Turner gave him by mistake, telling him that there are some good drawings in it. Arthur decides to give it a try and thanks him. Back in the room, the game inexplicably powers up by itself, spewing fog and light that covers the screen...

At the Sugar Bowl, Arthur is sitting at a booth when Buster arrives. As it turns out, he is now a creative writing professor, and Kate is in his class. He tells Arthur about a story she submitted in which babies can read the minds of animals. Francine and Muffy then walk in, with Francine wearing the latest model of sneakers from her shoe company while Muffy is carrying signs for her campaign to be mayor of Elwood City. George is now running the Sugar Bowl, while Binky is a weather reporter for a local news station.

The gang hears a whistle from outside, which proves to be D.W., who is now a police officer, accosting a motorcyclist who has parked in a no-parking zone. Unexpectedly, he turns out to be her old friend, Bud, whom she greets warmly while dutifully writing him out a ticket. They then come inside, where Arthur shows off what he's been working on: a graphic novel based on his childhood. Having been inspired to enter the field by the book he received by accident, he begins to read it to everyone, beginning with how he got his glasses...

Characters

 * Arthur Read
 * Buster Baxter
 * Muffy Crosswire
 * Paige Turner
 * D.W. Read
 * George Lundgren
 * Binky Barnes
 * Francine Frensky
 * Bud Compson
 * Brain (cameo)
 * Marc Brown
 * Slink (cameo)

Production notes

 * The adult D.W.'s speaking role in the final scene is the first time she has been voiced by a woman (Nissae Isen) in the entire series. With the exception of video games, she has almost exclusively been voiced by boys.
 * This episode includes several Easter eggs paying tribute to the series and its history:
 * Patrick and Rafi are prominently featured in the cold opening. Though neither speak, their presence is an acknowledgment of the show's history: Patrick's presence is a nod to his debut, the landmark episode "Mr. Ratburn and the Special Someone," while Rafi is voiced by Cameron Ansell, who voiced Arthur from Seasons 9 to 11.
 * Upon seeing a picture of an aardvark in the book on how to draw animals, Buster remarks, "I never knew their noses were so long." The very first Arthur book, Arthur's Nose, depicted Arthur as having an huge nose.
 * Muffy is running for mayor against Mayor Hirsch, a previously existing character named for head writer Peter K. Hirsch. Francine and George remark that he has been in charge forever and suggest that he retire, poking fun at their writer.
 * Marc Brown plays himself once again, interacting with his own creation for the first time in the entire series and encouraging Arthur to give drawing a try.
 * 22 years after he last played the role in Season 5, Michael Yarmush, the original voice of Arthur, reprises his role by voicing the adult Arthur. He previously voiced Jay in the 10th anniversary episode "Happy Anniversary" and has voiced Slink since Season 9.
 * Adult Arthur is the final character to speak in this episode, making him the final one to do so in the entire series. Fittingly, Michael Yarmush is the first voice heard in the series at the very beginning of "Arthur's Eyes," and the last one in this episode.

Episode Connections

 * The graphic novel Arthur published is "Arthur's Eyes", a reference to the first episode of the series.
 * Patrick previously demonstrated his experimental chocolate flavors in his debut episode, "Mr. Ratburn and the Special Someone." Buster ends up trying one in this episode and takes a liking to it.
 * George's hall monitor hat appears in the cold open. He first wears it in "The Hallway Minotaur."
 * Buster uses his inhaler in the library, which is a callback to "Buster's Breathless."
 * Buster gets excited upon seeing the book 101 Uses for Butter Churns. This is a reference to the events of "Buster's Amish Mismatch," including his attempt to make butter at home.
 * The events of "The Master Builders" are referenced in relation to Francine's future as a businesswoman.
 * Binky is shown to have grown up to become a weather reporter. He previously became interested in reporting in the season premiere "Binky Wrestles with a Story."
 * D.W. using a whistle and penchant for law and safety was first shown in "D.W. Blows the Whistle."
 * Muffy's political career was previously foreshadowed in "The Election."
 * Buster refers to Kate's story assignment about a baby who can read animal minds. This is a reference to "The Secret Life of Dogs and Babies" and other "dog and baby" episodes.