Chizuru Saito, 25 years old, has been dating her boyfriend (Yu Hirano) for five years. They are a happy couple...
Meanwhile, news of a class reunion arrives.
As they chat away after a long time together, Murai Kei begins to lean towards Chizuru. After being offered a drink by Kei, Chizuru becomes completely drunk and wakes up in a hotel room... She can't run away and instead surrenders to a pleasure she's never felt before. Yes, this one time was supposed to be the end... Even if she has sex with her boyfriend or uses a dildo, she can't get the same pleasure as she did back then. So where does Chizuru head to...? (͠≖ ͜ʖ͠≖)