The balance of Maira's world is shifting.

The responsibilities as the next Gatekeeper leave 12-year-old Maira with little time to play beneath the waves. Instead, she works alongside her father learning the role held by her family for generations.

On a rare free morning, Maira discovers an extraordinary underwater cavern that resembles a long untold legend. She and her friends decide to keep their find a secret. But when Maira is confronted by treasure hunters, she learns their secret has been betrayed. Evil has once again entered her world.

Maira must find a way to protect the sea and unite her people to restore the balance of history, a task she can't do alone. But the survival of her way of life and the sea itself depend on it.