Isami Hanaoka is the fifth grader in an elementary school and a cute girl. She came from America with her mother, Reiko Hanaoka, to Ooedo city where her grandfather, Kanryusai Hanaoka, lives in. Incidentally, her father, Kai Hanaoka, is missing for five years.

On the way going to new school, she was picked up by two boys. One person will present a rose flower, and will draw her mind, and one more person will hold her breast of her. Oh! Japan has also gone to ruin -- saying-- a joke. 

In fact, these two persons are her classmates of the same elementary school. And they knew having members of Sinsen-gimi in each ancestor. Three persons met again by that night and Hanaoka house, and they get the sword, Ryu-no-tsurugi, which their ancestor made here. In fact, the sword contained a stone called the Rumino-taito which produced the super-energy of a mystery. 

In order to fight with the Kuro-tengu party which planed world conquest, they formed Sinsen-gumi...