Mr. Tiger, Betsy, and the blue moon

Betsy K Glory, the daughter of a mermaid and an ice-cream maker, lives on an island that's been left off the map of the world where she wonders how to make wishes come true. She discovers that only Gongalong berries harvested when the moon is blue, then made into delicious-wishes ice cream will work. But even if you can find these rare berries, how do you turn the moon blue? With the help of Mr. Tiger, his troupe of circus acrobats, an enchanted...