Marin and Urin, two pure sisters, live alongside the fish in the sea, but yearn to be in the world beyond the water and above ground. One day, a beautiful ring falls in the middle of the sea, and Marin and Urin retrieve it. The two decide to leave their water-bound world for the first time to deliver the ring. After an arduous journey, they come across an isolated island where a high school girl named Kanon lives. The encounter between Marin and Kanon — the maiden of the sea and the maiden of the skies — awakens a hidden power as the world is threatened by an enveloping darkness.

Source: ANN

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