Hal Hollings

Humphrey, pet hamster at Longfellow School, learns that he has an important role to play in helping his classmates and teacher.

While continuing to help his classmates solve their problems, Humphrey, pet hamster of Longfellow School's Room 26, faces many surprises, like rolling in a hamster ball, a substitute janitor who might be an alien, and the possibility of Mrs. Brisbane retiring.