Hideki is a young man who lives with his grandmother after the loss of his parents. Despite the tragedy he finds simple pleasures in his everyday school life and playing with the music club, of which he is a member. He greatly admires the council president, Reina, who he meets in the corridors after school. Hideki's life is turned upside down once again and he finds himself drifting with nowhere to go.

Reina offers him a chance, an evening meeting between the two of them leads to Hideki taking on an entirely new life as her second sister, Miyako. But not everything is as it seems - and accepting the mercy of another isn't always easy.