Sanzokuou

Nagakado is an ordinary boy with an exceptional talent for traps, living comfortably with his father in a small town. Their family, however, keeps secrets he only partly understands: each generation inherits a black katana, far heavier than it appears and usable only by their bloodline, along with a star-shaped mark on the chest. When Nagakado inherits the mark, his father's begins to fade. After learning more about his family, Nagakado sees his father accused of treason and taken to a larger city. He follows with the heirloom sword, only to discover that his father has been murdered. Seeking revenge, Nagakado sets out on a journey and meets Natsume, a beautiful assassin. The two face an uncertain future together.