Eleven-year-old Jessa Newberry desperately wants to fit in with the popular girls but on the first day of middle school she makes a fool of herself in front of the whole class. On top of that, she's having these strange dreams about Sidney, a friend she hasn't seen since kindergarten. Together in the dreams they fly around Dreamland, a magical world with ice-cream trees and cotton candy clouds.

When Jessa meets Sidney in real life at a cancer fun run, she discovers that Sidney is having the same dream. When Jessa is diagnosed with Hodgkin Lymphoma and her friends from school stop talking to her, Dreamland becomes the place she wants to be, and Sidney becomes the best friend she's always needed.

But Dreamland is in danger. The ice-cream trees are melting, the candy has gone rotten, and children are disappearing. Even Sidney has gone missing. Can Jessa save both her friend and the haven she has grown to love?