Mitsurugi Ryouko is a high-school girl who intends to be a samurai. In her high school, there is a system named K Fights. It is a system which solves all the troubles by the duel of the school official recognition. And, Ryouko is a present champion of the K fights. The person who challenges to defeat Ryouko is unfailing, and her school life is a fuss every day.

One day, Ryouko obtains a mysterious pendant. And, she was somehow in another world after the pendant shoots light. There was a shrine maiden named Reiha in this world named Solvania Shadow. She calls Ryouko the ogre of Yenen. And, she says the work of Ryouko is to defeat the monster of this world by her.