"I will persue the Blade Children.." is the last thing Narumi Ayumu heard from his amazing elder brother, Narumi Kiyotaka, before he vanished. All his life Ayumu has followed in his brothers shadow who excelled at everything from detective work to the piano, yet Ayumu could never compare to his brother.
This left Ayumu with no confidence in himself despite his own excellent talents, until one day he finds himself locked into the great mystery which revolves around a group of High school kids known as the Blade Children. Ayumu wishes to simply find his brother by figuring out who exactly these Blade Children are, however, they seem to have a different idea in mind.