Twelve-year-old Fin drags his reluctant father on a diving hunt for a missing treasure, hoping that finding the family legacy will help his ailing Abuelo.

Sia practically grew up in the water scuba diving, and wreck dives are run of the mill. Take the tourists out. Explore the reef. Uncover the secrets locked in the sunken craft. But this time … the dive goes terribly wrong. Attacked by a mysterious creature, Sia’s boat is sunk, her customers are killed, and she washes up on a deserted island with no sign of rescue in sight. Waiting in the water is a seemingly unstoppable monster that is still hungry....