Surprise and fear stiffened my body and I couldn't make a voice. Ryo Fukutomi, who was the first victim of Slut, could only endure with her eyes closed. Such a reaction is a good target for Cuckoo. Ryo was squid on the train and was raped in the toilet at the station where he ran away. It's been a few days since then. Ryo remembered that experience many times and began to indulge in masturbation. That should be the worst experience I want to forget. But ... I've never felt that way. Ryo, who feels disgusted by the filthy people but also feels an uncontrollable urge in herself, decides to board the train that the lewdness awaits again.