Seven schools in the district of Kantō are constantly at war with each other. The lives and fates of certain students are guided by jewels, called Magatama, that contain the spirits and destinies of warriors from the Three Kingdoms period of China. The ultimate purpose of each of these tōshi is to get stronger than all others and become the eponymous Ikkitōsen. Hakufu Sonsaku recently moved to Tokyo and is apparently destined to unite the schools, just as her counterpart united seven countries long ago. The others find it hard to believe in her, as she consistently shows a lack of common sense and intelligence. However, the magatama that her mother Goei passes on is rumored to be infused with the spirit of the legendary warrior Sun Ce. All Hakufu herself cares about though is fighting whomever happens to be up for a rumble - in fact, fighting even excites her - which causes embarrassment and frustration to her cousin Shuyu Koukin, with whom she is staying.