A city in which an epidemic of a sexually arousing virus rages... The main characters are in great danger because they are stuck in the middle of an infected city. Pursued by hordes of infected maniacs, Hiroshi Ookura and his friends seek salvation in a mall that looked unscathed. But madness and death are everywhere... It begins with the two oyashas waking up in a school bus, not remembering what happened or where they are. In fact, then their adventures through the sinful city begin.