Yoko Nakajima is an ordinary high school student with ordinary teenager's problems (school, friends, parents, you name it). On top of suffering from having gruesome nightmares of monsters and gory mayhem, her parents are trying to get her to change her hair color! Still, things are not that desparate until one day, she gets an after-school detention for falling asleep in class. That's when things start happening at a frantic pace as if one of her nightmares took on a life of its own. A tall blond stranger comes to her and tells her she's his "King." A gigantic and ferocious bird then materializes and attacks the school, and the stranger (who calls himself Keiki) summons up other creatures to fight off the bird, and gives Yoko a sword, telling her to fight with it. She's no Buffy the Vampire Slayer (yet) and refuses to do so, but then her body is taken over by a spirit summoned up by Keiki, and this spirit (in Yoko's body) kills the bird in time before it could inflict fatal damage. Keiki, the spirit, and a wolf-like creature transport Yoko to the world of 12 kingdoms through a space-time distortion. Attacked by strange beasts in a strange land, and separated from Keiki as a result, she's got no choice but fight to survive...
This alternate world sets the stage for Yoko's wild adventures, not to mention an exciting learning experience like no other.