Jushiki (=spell formulae) is a special ability in this world. They are chemical reactions in weapons that seem like magic. Two people who use this kind of magic are Gaius and Gigina. Gaius is the one who deals with dangerous situations thanks to being quick-witted and Gigina is a beautiful but cruel swordsman. Even though they seem like enemies, they work together well in battle, as if they were one person. It is a dark fantasy story in which both of them fight to survive.