Gray is already bigger than all the other sharks in his clan, or shiver. He can't stop growing, and when his hunger gets him into trouble, he's banished from the reef with his best friend Barkley. Their hunt for food forces them to journey deep into Goblin Shiver territory, where they have no choice but to join the shiver. They'll help fight against rival sharks in return for training, protection, and food. But who can Gray and Barkley trust when...

Gray is already bigger than all the other sharks in his clan, or shiver. He can't stop growing, and when his hunger gets him into trouble, he's banished from the reef. Luckily his best friend Barkley comes with him ... but their hunt for food forces them to journey deep into the dangerous Big Blue.

Everywhere Gray and Barkley swim, fish are whispering of a growing threat, of a shark named Finnivus who will eat anything or anyone, and won't stop until he has seized control of the entire ocean. Finnivus has an armada of vicious battle sharks to help him expand his empire, and Gray realizes that it's up to him to save the Big Blue. But first he must train with Takiza, the wise and mysterious fighting fish who has promised to teach his young apprentice...

Learning that his wise mentor, Takiza, may have been responsible for his father's death, Gray begins questioning everything he ever believed while preparing for an imminent war against dangerous prehistoric sea monsters.