A major typhoon that occurs once every few years. I thought I'd go home early today, but before I knew it, it was already the usual time. The trains were out of service, the roads were flooded, and I ended up staying at school. At that time, "Teacher, what are you doing up until this time?" Utsumi, a student, was also left behind at school. The two of us were alone in the spacious school building until morning, and a dangerous and lewd night was about to begin.