Ao no Shima to Neko Ippiki

Souta Nakamura, a young city teacher moves to the island of Nagishima after spending years away, expecting to meet his old upperclassman who offered him lodging, but finds out that he's gone and he's left him to take care of his teenage daughter Ao, a girl who is wise beyond her years, and who has the quiet island lifestyle ingrained in her heart.