After fire fighters visit Ms. Day's classroom, Fluffy gets a chance to see what they do firsthand.

Fluffy the class guinea pig joins the students on a trip to the museum, where he carefully studies the exhibits and imagines tracing his ancestry back to the dinosaurs.

Fluffy the guinea pig enjoys himself when Ms. Day's class has a party to celebrate the one hundredth day of school.

While his human Elliot adjusts to his new home and stepfamily, Gizmo, an evil genius guinea pig, searches for a new evil lair where he can plot to take over the world, but Gizmo is constantly thwarted by Elliot's little stepsister Jasmine (who likes to play dress-up), Abuela (who may or may not like to eat cavies), and Wedgie (a Corgi superhero and Gizmo's nemesis).

A young guinea pig describes situations that make him sad, how it feels to be sad, and how he can feel better.