Norman, a porcupine whose best friend is a tree named Mildred, begins to feel jealous when another tree grows close to Mildred and acts out against the new tree.

Pippa is the only porcupine in her class, and with Valentine's Day approaching, she feels lonelier than ever until she finds her name on a classmate's love list and sets out to find out her mystery friend.

When the Tate family dog, Ajax, has a run-in with a porcupine, things get prickly--and dangerous--quickly. It'll take Callie's quick thinking and doctoring, along with a little help from Dr. Pritzker, to make things right. Will Ajax learn to leave other critters alone?