Karate Girl

Ayaka and Natsuki are the youngest desendants of a legendary Okinawan karate master. As children, they live a happy life until their father, kidnapping Natsuki, and stealing the black belt that has been passed down in their family for generations. Several years later, Ayaka is living the humble life of an ordinary high school student while Natsuki has been trained as a killing machine by the mysterious group that kidnapped her all those years ago.