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.
You're the one who told me 
to go under, remember, old lady?
أنتِ من طلب منّي النّزول، أتذكرين
أيّتها الآنسة العجوز؟
Das war doch deine Idee, Tantchen.
Fue idea suya, señora.
Fue idea suya, señora.
Tu me l’as demandé, l’ancienne.
Vecchia, sei stata tu a dirmi di scendere.
Não foi você quem disse
para mergulharmos, velhota?
Так вы ж сами это затеяли, тётенька.
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