As the next generation of beast master, Su Moxun entered high school on his 16th birthday with the Xiuyan phoenix-carved jade pendant passed down from his ancestors. The vague memories of the ten-year-old, the mythical beast Yuxi who was once her best friend but is now estranged, and the mysterious and confusing Japanese boy Natsume Kiyokazu will gradually make her look back at the untouchable abyss in her heart: the secret about her grandmother's death when she was ten years old...