The pamphlet for the project describes the setting as Japan in 2093. A rural town that used to be the most prestigious town in the world has long since sunk 30 meters under the ocean's surface. The story is a tale of a girl who takes part in free diving (diving without the aid of equipment to breathe), and the emotional growth she experiences.

Gainax intends to air the anime for two cours or half a year. At FanimeCon 2015, Gainax co-founder Hiroyuki Yamaga mentioned that he was working on a project about a female free-diver and that it would be unveiled soon.

[Source: Anime News Network]