Betty loves to read all about Amber the Brave's adventures in her favorite book series. She also loves to pretend she's on an adventure just like Amber—flying through the air and saving the day. But when Betty's daydreams turn into reality, she'll need to conquer a supervillian for real. Or she'll be stuck inside Amber's Big Adventure forever.

Nine-year-old Betty Hilmar thinks her life couldn't possibly be more boring. That's why she's always reading her favorite book, Amber the Brave. Amber gets to battle supervillians, slay dragons, and have incredible adventures that Betty only dreams of. But everything changes when Betty receives a mysterious new book.

Suddenly, Betty finds herself in the middle of one of Amber's top secret missions. Together, she and Amber must stop the evil Doctor Sly from taking over the world, and as they race from one danger to the next, Betty learns that being a sidekick is no piece of cake.