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.
Is that thing actually 
gonna survive underwater?
هل ستنجو هذه تحت الماء فعلاً؟
Glaubst du echt,
du kannst mit dem Ding abtauchen?
¿Seguro que se sumergirá?
¿Seguro que se sumergirá?
Puoi davvero immergerti con questo affare?
A gente vai mesmo conseguir
mergulhar com isso?
В ней точно можно погружаться?