Hannah looks forward to Robin Hill School's celebration of one hundred days of classes, but when a cold keeps her home the day of the party she decides to bring in the one hundred buttons she found anyway.

A young child imagines kindergarten as a mission in space, with his fellow kindernauts, and this is their one hundredth day.

"In their fourth adventure, classroom mice Fergus and Zeke--after a few false starts--jump into a creative project to help the kids mark the one hundredth day of school. Fergus and Zeke love being the class pets in Miss Maxwell's classroom, and they do everything the students do. But when the kids start collecting items and doing gym challenges and making projects to celebrate the one hundredth day of school, the mice can't seem to find a way to join...