Ryosuke Miyahara had failed in love in his hometown, but he thought he could have a wonderful romance at a new university. However, that hope was not fulfilled and he failed again, leading him to believe that romance was impossible for him. After that, he preferred to hang out with his friends rather than pursue romance, and he became very close with one of his female friends, Misaki Kazaoka, because they shared common interests such as games and their personalities matched. Misaki had also failed in love like Ryosuke and had no intention of making a lover anymore, which further strengthened their friendship and they began to hang out often.

Some time later, they ended up having a physical relationship to relieve their sexual desires by chance, and they realized that their physical compatibility was better than they expected. Since then, they also had physical relationships to satisfy their sexual desires, but their relationship as friends never changed. This easygoing relationship was what Ryosuke wanted, and unlike a lover that would eventually break down, he thought it would last forever.

However, that relationship would change due to the existence of a certain man—.