As a child, Ruka saw a ghost in the water at the aquarium where her dad works and now feels drawn toward the aquarium. Ruka meets Umi and Sora, two mysterious boys who were raised by dugongs and hear the same calls from the sea the she does. Ruka's dad and the other adults who work at the aquarium are barely aware of what Ruka, Umi, and Sora are experiencing as the kids find themselves involved in the mysterious worldwide disappearance of the oceans' fish.
General Note
Printed Manga-style: book opens from left to right; pages are read from right to left.
Translation of: Kaiju no kodomo.