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.
Oh, you're so useless!
!أنت عديم الجدوى
Mensch, du bist auch keine Hilfe …!
No sirves de nada.
No sirves de nada.
Tu ne sers vraiment à rien.
Quelle déveine !
Uffa, è inutile!
Ahh, mas que inútil!
Какой же вы бесполезный.