The members of the Hadogumi went camping during their summer vacation. Hiroshi and his friends look back on the days of their battle with Matenro. If you think about it, Matenro should have been a fictitious existence in the first place. However, when he actually appeared, the Hadogumi was formed and continues to this day. Matenrou is an existence that I will have to overcome someday. The five people changed their minds.