Youko was a 16-year-old living a fairly ordinary life as an honor student in Japan, whose primary worry is her naturally red hair. One day at school, a man named Keiki suddenly appeared and bowed at her feet, swearing loyalty to her. The school was then attacked by a giant bird, and she reluctantly accepted his protection. He gave her a sword and transports her and two of her classmates to the kingdom of Kou.