After three years Mimi comes back to the island where she had spent her childhood. She is greeted by her childhood friends Yousuke, Sumire and Hikari. Heartbroken in Tokyo, she has now came back to the beautiful island surrounded by the deep blue sea. But among this four friends, friendship soon turns to love…!? A blue world spreads before your eyes, an unforgettable story begins.

Depois de três anos, Mimi voltou para a ilha que ela morou quando criança, onde ela fez 3 grandes amigos, Yousuke, Sumire e Hikari. Ela voltou de Tokyo, para a linda ilha onde viveu, para tentar curar seu coração partido. Mas entre esses quatro amigos, a amizade logo se transforma em amor ...?