The sea has always called to Sofia, even when she and her mom lived in a big city nowhere near its shore. That's how Sofia always knew she was a mermaid--that, and the fact that the sea and its creatures are much easier to understand than people. Like her mother, who is sending Sofia away instead of her barracuda of a boyfriend; that's a flying fish if Sofia's ever seen one, spending so much time reaching for the sky she can't see what's going on below the surface. When Sofia meets her abuela, she knows she's up against a sea dragon: fierce and guarded, but maybe not so bad when you're the one she's guarding. Still, Sofia longs to meet another mermaid, someone who understands her and the sea completely.

When Sofia meets Louisa, it seems like she's found just that--until the sea betrays them both in one irreversible moment. Soon their town is overtaken by hurricanes and floods and emotions and questions so big Sofia doesn't know what to do with them. Like, how do you catch a flying fish? How do you make friends with the sea again? And how do you calm the rough waters within yourself?