Y/n Nomura, as well as his Cousin who are the same age as you, Fudou Nomura, but instead of acting like cousins, they act like real sibling thanks a bond they share for each other. Now the two Cousins are transferred to a Private School, Aichi Symbiosis Academy, which was an All-Girl turned Co-Ed schools, but because of the new rule, girls were permitted to bring weapons for "Self-Defense". This rule permited the creation of the Vigilante group, Supreme Five Swords. Now we take a look at the 2 Cousin turned Siblings handle their new school and maybe attain their dream of a peaceful life.