One day, while Guest was living a quiet, solitary life in the mountains, a strange presence was felt. Upon opening the door, a woman with white hair, lime-green eyes, and a red uniform was standing there.

It was suspicious enough that she had come all the way into these deep mountains, but instead of stating her business, the woman just stared intently at Guest's face. Then, as if confirming something, she drew the sword at her waist.

For Guest, it was nothing short of absurd. A complete stranger showing up at his house and demanding a duel out of the blue—there was no way to make sense of it.