Tomohisa, an ordinary student, receives an unexpected note that leads him to a private meeting with the beautiful senior Mizuho, whose earlier glances had already caught his attention. The encounter lingers in his mind the next day, distracting him during class until he realizes his friend Endou and classmate Mikura are both missing. Worried about what they might be doing, he discovers the pair sharing their own intimate moment on the fire escape, stirring his quiet jealousy and curiosity.