As a terrible evil spreads through the Bravelands, causing families to split and longtime allies to turn against each other, Bramble, Chase, and Prance seek help from the Great Father, who may not be able to save them this time.

When she incurs Neptune's wrath by finding a diamond ring buried under rocks in the ocean, Emily is put under a curse that will force her to choose to be either a mermaid or a human and split up her parents forever.