In the sixth book, an earthquake shakes Zoey's house. Or maybe it's a unicorn-quake? An enormous new friend arrives in a lot of pain, and it's getting worse every day. Zoey must work with her mom and Sassafras to find a cure—and quickly!

Each story in the Zoey and Sassafras series features a new magical animal with a problem that must be solved using science. There isn't a set formula for each book; Zoey sometimes needs to run experiments, while other times she needs to investigate a mystery, and yet other times she needs to do research. Zoey models how to keep a science journal through her handwritten entries in each story. Each story is complete with a glossary of the kid-friendly definitions for scientific terms used. The series highlights child-led inquiry science and the topics covered align with both Common Core and Next Generation Science Standards.