Nightblade Academy is the most prestigious academy dedicated to cultivating the finest assassins, gunmen, mercenaries, and military officers in the world. Sieg Brenner is the new and mysterious transfer student, the disciple of a legendary assassin. He immediately gets the attention of Yumi Hasegawa, the Scarlet Queen and the top-ranking student in the Academy, during his first day of school. Will he survive on his own? Or will he become another one of the Scarlet Queen's broken toys?