Miki and Ai enjoyed chatting and drinking beer together by themselves from time to time. One day, Ai confessed that she had been with a man. The man was Masahiko, who had chased away a molester (Toru) on a crowded train. However, Toru and Masahiko were in on it. In the end, Miki and Ai chose lesbian pleasure over men. Koji, who lived next door to the apartment, was bothered by her moaning. On the train, he met Sayuri, a student from his days as a tutor, and his desire was stimulated. Emi, who used to live with Toru..