Hiyori Yuki

Shunsuke, orphaned as a child, is a pessimistic young man. One day, drawn to a mysterious song next door, he meets Setsu, an older woman.

After Mana's sudden disappearance from her room; her sister, Ako, finds a website on Mana's computer. In Ako's ongoing search for Mana, she notices strange things about the website that she should not have uncovered.