In the near future, much of the world has been forgotten at the bottom of the ocean due to rising sea levels. Natsuki Ikaruga, who lives in a small town surrounded and stranded by the sea, is invited by a mysterious woman, Catherine, to search for a treasure in his grandmother's house who was a marine geologist. One day, he dives to the bottom of the ocean in a submarine and encounters a mysterious capsule with a girl sleeping inside. The girl was a humanoid so sophisticated that she could be mistaken for a human.
...in a world like this.
في عالمٍ كهذا...
Auf dieser Welt …
Con el mundo así…
Con el mundo así…
sur cette maudite planète.
in questo mondo.
...num mundo como este.
в таком-то мире.