he plot resolves around a teenaged boy called Ayumu Narumi. Two years before the series, Ayumu's brother disappears without saying bye or where he would be. Though he did give one hint, the Blade Children. Ever since then Ayumu had been trying to figure out what the Blade Children were or how they are connected to his brother. Ayumu meets a girl called Hiyono Yuizaki, who by the way is very nosy, and tries to help him find the Blade Children.

As the story goes on, he meets all the Blade Children, who all challenge him to different games that lead to life or death situations, and he finds out that they are all missing a seventh rib bone and have a curse of some sort. This just puts more questions in Ayumu's head. Will he ever find out the curse of the Blade Children? How is this connected to his brother? Only fate will tell.

Blade Children are born missing their 7th rib, and apparently have a mark on the right side of their body.