Yasha (Yoshida, Akimi)

Arisue Sei is a youth who lives alone with his mother on an outlying island of Okinawa. Though his mother is quiet and fears being conspicuous, they were living happily. But on a certain day, that tranquility is suddenly destroyed. Sei's mother is killed by a group of mysterious men, and he is taken captive. What kind of secret does he have!?