Sen is a first year student in Karasuda Private High-school. In this high-school, in-dorm students aren't provided any lunch or dinner supposedly to make them take care of themselves better. As a result, a group of students and random youngsters with poor allowances decided to fight with each other in various supermarkets in order to get half-priced ben-to; and the most renowned of these fighters are known as "Wolves." One night, Sen entered one of these supermarkets and unwillingly got dragged into a fight with them until she is saved by a very famous one: the "Wizard" Kaneshiro Yu. The later proposed her to enter in the world of the ben-to fighting and this where her formidable adventure begins. (Source: MU)