Nagi-Asu: A Lull in the Sea

In ancient times all people lived in the sea. But people were drawn to land and they left the ocean. Having stepped onto land, they could no longer return to the marine realm. Childhood friends Hikari and Manaka, who lived together in the sea, along with their friends Kaname and Chisaki, are forced to go to school on land because their native underwater school has closed.