Misaki Yoshimori, your best friend Yuuji, and you, Tatsuhiko Saito.
The three of you spent your days at school with a friendship that most would envy.

Yet, it is so easily broken.
Despite knowing your feelings for Misaki, Yuuji tells you he confessed to her, unable to go out with her if it meant lying to you.

In response to your friend's honesty you can only support him in his relationship with Misaki.
However, a small darkness is borne in your heart and mind.

Since that moment, it's as if an invisible barrier exists between the two of you, and things become more and more serious.

Feelings of guilt, more and more lies.

You become torn apart, a different person by day and night.

All this is because... you and Misaki have become addicted to the pleasures of each other.

[Description inspired by, and partially translated from, http://www.getchu.com/soft.phtml?id=420145]