Japanese anime feature based on the manga by Daisuke Igarashi. High school student Ruka Azumi (voice of Mana Ashida) spends her summer holidays at the aquarium where her father works. Over the course of the summer months Ruka bonds with brothers Umi (Hiiro Ishibashi) and Sora (Seishu Uragami), who were raised by marine mammals and are reported to have special abilities. As a comet impacts on marine life and a small pod of whales exhibit strange behaviour the three teenagers attempt to uncover the mystery.