14 year old Cora's life isn't all that great. Her father just died in a car accident and she's stuck living with her abusive step mother, Frances. But everything changes when she goes with Frances on vacation to Hawaii, and discovers she's a mermaid. To make matters even more complicated, she finds out she's more than just a mermaid. She's a lost princess to the underwater city of Atlithica. Can she rein her inherited powers enough to battle off the rival city who destroyed her family's kingdom, or will she fail, ending the life of everyone around her?