The law of the sea is give and take, ebb and flow. Long ago, it took Lynnette's brother. Now, it's brought her a friend. Or is he an enemy?

Hidden away in an island cove, the Convent of Saer is a peaceful place guarded by mermaids, filled with endless sunlight and brightly clothed nuns. Despite the beauty around her, ten-year-old Lynnette is terribly lonely. In the midst of a frightening storm, she prays for a friend. The next morning, a half-drowned boy washes ashore.

Maddox is not what she expected. Clearly distrustful from the start, the eleven-year-old stranger cries too much and is skeptical of the Convent's beliefs. If that weren't bad enough, he's the son of an emperor who wants to conquer Saer. When a royal guard arrives to track down the prince, Lynette and Maddox's newfound friendship is put to the test. Lynnette must confront the Convent's fear, protect her home, and face her own past before the friend the sea gave her is taken away.