The Hirose family has been protecting the area of Funabashi, Chiba since ancient times. The parents of the siblings, who are descendants of the Hirose family, passed away early, and the elder brother (Hayate) carefully raised the younger sister (Kodama Momoka), and they both devoted themselves to training together. Then one day, the evil organization "Corona" appears.Their bio-terrorist plan threatens the peace of Funabashi.This is where the Hirose siblings, heroes in their own right, come in.However, the older brother is unable to go on a mission due to a deep wound, and the younger sister has yet to go on a mission. Just when they are about to give up, ...... the beloved sister stands up and vows to her brother to carry out the mission! The "first mission" seems reckless for just one person.Will she be able to protect the peace of Funabashi? To protect what is important to you! Beat up a group of powerful enemies! Hero is close by!