Haruka, who teaches at a famous prep school, is troubled by the label she has been given by those around her as shy. While feeling confused by the public's view that even drinking parties are not tolerated, the principal instructs her to scout the area for the school trip with her colleagues. However, the inn they arrive at turns out to be a mixed-gender hot spring. "Wow... there are so many penises..." Haruka gasps at the extraordinary sight, and the sense of freedom she feels on this trip also helps...