In her last autumn of the student, she and her childhood friend Nao begin dating after a long-awaited wish. I aimed for the same university, but I was the only one who failed the entrance exam. After passing the exam, Nao decides to move to Tokyo first. "I'll write a letter!" I was encouraged by the letters sent regularly every season, and I also felt like I was being dyed by the city, which made me feel mixed up. Meanwhile, Nao ends up having a physical relationship with a senior she met in college due to the energy she drank for the first time. A pure country schoolgirl gets dyed by a man's dick every time the season passes...