Pal goes missing after Arthur leaves for his friends' water balloon fight because Arthur has forgotten to feed Pal. However, he and Buster are certain that D.W. did it, but D.W. denies any involvement. Arthur and his friends mount a search throughout Elwood City for the missing dog.
Arthur is going to feed Pal when Buster comes and crashes into everything. D.W. is trying to go to the Mary Moo Ice is Nice Extravaganza. Arthur and his friends have a balloon fight and Pal waits to get fed. He drinks his water bowl Arthur told him about. He needs to pee, but no one knows. He tries to pee on the carpet but he remembered that Arthur told him don't pee on the carpet. He runs up stairs to D.W., but she shuts the door on him. Pal cries and whines to Arthur at the window but he gets hit by a water balloon from Francine. Arthur and them leave to the Sugar Bowl. Pal runs to the bathroom, he tries to pee in the toilet like everyone else. He tries to step carefully but he flushes the toilet with his paws and falls in to the toilet. Arthur was saying "It wasn't fair just. Francine was right there. Pal started to scratch the glass!" He remembers that he needs to walk Pal he searches everywhere but nowhere. That's when the search starts. They all split up and look for Pal all over town. However, none of them find any sign of Pal. Then Arthur and Buster find Pal's paw prints, which Buster makes a cast of. At that moment announces that Pal was missing and insults him. Arthur and Buster get suspicious and start questioning D.W. They find out that Pal was in the bathroom trying to get out of the toilet. Meanwhile, Pal is traveling all over town.
- Francine Frensky
- Muffy Crosswire
- Prunella Deegan
- Binky Barnes
- Brain Powers
- Timmy Tibble
- Tommy Tibble
- Jane Read
- David Read
- Kate Read
- Pal Read
- This is, to date, the only feature-length production from the Arthur franchise.
- This is one of the few Arthur productions not to be produced by its main production company Cinar/Cookie Jar. The film was produced by WGBH Boston, Lionsgate, and Mainframe Entertainment, with the animation/production services being handled by RichCrest Animation (or Crest Animation, as they were later known as). It is also the only production from the series to be produced direct-to-video.
- Most of the cast in this movie used pseudonyms instead of their real names as this production was non-union in contrast with the TV series which is union-contracted under ACTRA and occasionally SAG-AFTRA.
- This movie's plot is similar to the SpongeBob SquarePants episode "Have You Seen This Snail?", in which Gary runs away after SpongeBob forgets to feed him.
- In 2007, this film was nominated for a Young Artist Award for Best Quality Picture, Sound, and Animation. It was beaten by Disney and Pixar's "Cars".
- Mary Moo Cow is referenced in this movie (specifically, Mary Moo Cow on Ice from the World of Tomorrow introduction flashback).
- This is the first movie seeing all the characters in 3D form instead of 2D form.
- Pal is referred to Lucky by the zamboni/truck driver.
- This is the first movie not to feature the theme song at the beginning.
- When Buster, Dad, and Arthur are in the Mr. Kone's Ice cream factory, the background door is still locked.
- Main article: Arthur's Missing Pal/Gallery