Mizuo (Mizuho Kaito), Toshio's aunt, invites him over with the words, "My husband's away on a business trip and I'm feeling lonely, so come visit me once in a while." Toshio can't suppress his racing heartbeat. Mizuo has been his first love since childhood, and the chance to spend time alone with her makes his heart pound. Arriving eagerly at his aunt's house, he finds Mizuo as beautiful as ever, radiating the same charm she always had. But the feelings stirring inside him upon seeing her are completely different from those of his childhood. Confused by this change, Toshio is overwhelmed by an intense, uncontrollable lust rising deep within him.