From the New York Times bestselling author of Esperanza Rising comes a riveting story that blends myth, fantasy, and reality into an entrancing adventure, perfect for fans of Meg Medina, Kate DiCamillo, and Rick Riordan.

"An inventive, absorbing novel." ―New York Times Book Review

★ "Glistens like sunlight on waves." ―School Library Journal, starred review

★ "Ryan's skill as a writer shines." ―The Bulletin of the Center for Children's Books, starred review

★ "Lingers like the echo of thunder―powerful, haunting, and deeply core-shaking." ―Shelf Awareness, starred review

Sometimes the only way to hold onto what we love is to let go.

Kai Sosa is so passionate about swimming he is practically a fish. This summer, he's determined to become the athlete he once was on an elite swim team.

But something invisible holds him back. His race times are off. Dreams of his sister Cali haunt him. And he hasn't found her missing gold cuff, her last request. Mom is still talking about grief, even though it's been two years since she disappeared. He's fine now, isn't he?

When Kai discovers a library book Cali had checked out multiple times-about an underwater realm and a mysterious place called the Library of Despair and Sorrow-details from the story begin to appear in his own life: dolphin pods, imposing rock towers, unusual sea creatures, and even Cali's beloved bracelet. As myth and reality collide, El Niño unleashes its fury, and Kai is swept up in a storm of events that will change his understanding of love, death, grief, and how best to honor those we've lost.

Exquisitely packaged with breathtaking illustrations by award-winning artist Joe Cepeda and printed in blue ink.