Two years ago, the death of Naoto Watari's parents left him as the sole caretaker for his younger sister Suzushiro "Suzu" Watari and forced him to move in with their aunt. So devoted is he to Suzu that he refuses to join clubs or even hang out with anyone, earning him snide comments and the title of "siscon" at his new school. But as long as Suzu is safe and happy, Naoto doesn't care what everyone else says. However, his sneering classmates may turn out to be the least of his worries. The sudden transfer of a girl named Satsuki Tachibana brings back traumatic memories from his past-a past she had a hand in making so unpleasant. Nasty secrets, unknown to Naoto, begin to surface with her arrival, threatening his new life.

A modest country Dojo master is called by his legendary student to be special instructor for the Knights' order. This starts his reluctant journey, marked by choreographed duels, to win over his and others' doubts.

Two high school students hide their arranged marriage as their mutual hatred slowly turns into something softer.

When a traitorous retainer murders his family, young Tokiyuki has only one choice: flee now so he can fight to win back his birthright another day!