During a job-shadowing day, Binky follows Bitzi at the Elwood City Times, and Harry Mills (from “Bitzi’s Beau” and “Bitzi’s Break-up”) teaches him how to write boring stories in an exciting way that will capture the reader's interest.

Bud finally learns the real story behind how D.W.'s snowball (from “D.W.’s Snow Mystery” and “Return of the Snowball”) disappeared from the freezer.

George struggles to carry on conversations with adults, but makes a new friend with an equally-awkward older man when Mrs. Lundgren brings him to a party.

Arthur and his friends see a silent movie at the Gaslight Theater when they are trapped inside during a rainstorm.

Muffy's attempts to console Francine after Bubby (from “Is That Kosher” and “Grandpa Dave’s Memory Album”) passes away, but fails to make her feel better. So George teaches Muffy how to be a good listener.

The Reads find new ways to have fun at an old vacation spot.

Buster's friendship with Arthur is strained over his inability to keep secrets.

In an old section of the library, Arthur, Buster, Francine, and Muffy stumble across a board game that predicts their future careers. However, the game gives vague answers and runs out of battery power before Arthur's future can be predicted. A patron at the library then recommends Arthur keep the book Ms. Turner accidentally gave him about how to draw animals. 20 years later, Buster has become a college creative writing professor with Kate as a student; Francine runs a business that makes tennis shoes; Muffy is running for Mayor of Elwood City; George now owns the Sugar Bowl, which he has redesigned as the Sugar Bowl Café; Binky is now a TV weatherman; Bud returns to Elwood City, only to be ticketed by D.W., now in the police force; and Arthur is finally about to publish his own graphic novel based on his childhood, telling the story of how he got his first pair of glasses.

Note 1: Marc Brown, the writer of the Arthur books, voices the library patron who encourages Arthur to keep the animal drawing book.

Note 2: Michael Yarmush, the first person to voice Arthur, through seasons 1-5, provides the voice for adult Arthur in the final scene.

Note 3: “All Grown Up” is the final episode of the entire Arthur series.