Twelve-year-old Nani Sacro is used to skipping school to surf along the Puerto Rican shore. Yet something about the water has begun calling to her. And she soon discovers that her connection to the ocean goes beyond surfing.
With the help of her brainiac best friend, Agnes, the two discover that Nani can see underwater. And her abilities only grow from there. Yet controlling those abilities is a whole other matter, especially when she's never believed that she was as talented or smart as other classmates or even her older brother.
But when a new creature from the depths of the ocean threatens Nani and everyone she cares about, she must step up and learn to harness her abilities. After all, the fate of all beings, both underwater and land-dwelling, hangs in the balance.