The heroine "Sae Yamanaka" and the main character "Hiroshi" have been in love since their childhood.
Currently, they are in a long-distance relationship because Sae is attending a university far away from home.
One day, Hiroshi goes to her house and he hears Sae moaning from inside.
Hiroshi is shocked and angry that she is having sex with a man other than himself, but at the same time, he feels a powerful arousal that he has never felt before.
At the same time, he felt an intense excitement that he had never felt before...