Ruka is a young girl whose parents are separated and whose father works in an aquarium. When two boys, Umi and Sora, are brought in to the aquarium, Ruka feels drawn to them and the mysteries of the ocean. As the three children grow closer, they discover a secret connection between themselves and the sea that changes their lives forever.

Mana Ashida, Hiiro Ishibashi, Seishu Uragami