One day during winter classes, Hajime is invited by his expressionless classmate Suzu to the club room, where he experiences sex for the first time. Suzu knows that Hajime is in a long-distance relationship with a college boyfriend, and it's precisely because of this that she approaches him. That day, Suzu jokingly says, "I'm glad you weren't a virgin. It'd be troublesome if you fell seriously for me, right?" From then on, throughout winter classes, their secret relationship deepens in various places—bathrooms, the infirmary, and more. An irreversible winter break unfolds, intertwining bittersweet emotions and sweet memories in this melancholic love story.