Small for his age but artistically talented, twelve-year-old Jeremy Thatcher unknowingly buys a dragon's egg.

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).

Lulu's parents refuse to give in when she demands a brontosaurus for her birthday and so she sets out to find her own, but while the brontosaurus she finally meets approves of pets, he does not intend to be Lulu's.

Humphrey the classroom hamster has adventures going to the library, learning about the ocean, and sailing across a pond on a sailboat.

Garnering attention after painting a picture of his new pet goldfish, Pete the cat receives so many requests to make paintings for his neighbors that he devises an uproarious solution.