Charles needs an idea for his science project fast! But when the Petersons take in Roxy, a Cavalier King Charles spaniel and Chihuahua mix with an injured leg, Charles has an idea. Can Charles train this new pup using the scientific method and help her find a new home?

This puppy is quite a handful. He doesn't listen, he's obsessed with his toy sheep, and he can't ride in the car without...um...getting sick. Has Lizzie met her match, or will she be able to train this pugnacious pug?

While walking in a snowstorm, Lizzie sees two dark eyes and a little black nose. It's Spirit, a white German shepherd puppy! Spirit's owners found new homes for all of his brothers and sisters, but they still don't have a place for him. Can Lizzie find a forever home for this helpful little pup?

Meet Louie the Landseer (a Newfoundland with black-and-white coloring). He's adorable now, but he'll be a huge dog someday. Can Charles and his soccer teammates find Louie a big enough home?