Umi Monogatari: Anata ga Ite Kureta Koto

The story

Synopsis

Marin and her younger sister Urin, inhabitants of the sea, surface carrying a lost silver ring and set out to return it to its owner. On land they meet Kanon, a girl coping with recent heartbreak, and an unlikely friendship begins to form between them. Strange occurrences suggest ancient powers tied to the divide between sea and sky, pulling the trio into a…