One night on her way back from shopping at Kagami Mall, Sakuno Uryū gets lost and she calls her older brother Shingo to come find her. With initially no luck in finding her, and with her cell phone battery nearly dead, Sakuno gets help from a girl passing by, who offers to call Shingo. Shortly afterwards, Shingo meets up with Sakuno and the girl who helped her, Airi Sena, in a nearby park. Shingo, Sakuno and Shingo's friend Hayata Mukunashi, who attend Kagamidai Private Academy, are three of the students chosen in a group to take part in a temporary ten-month transfer to Yuijo Private Academy, which until now has been a prestigious all-girls school. Upon entering the school grounds, they meet Angelina Nanatsu Sewell, a student and maid at the school. Airi forcefully brings her mother and principal of the school to meet the group from Kagamidai, who were waiting for her arrival.