Before being forced into a marriage with Crown Prince Friedrich "Freed" van de la Wilhelm, Lidi von Vivoir lived a simple life in Japan. However, due to her past experiences, she wants to avoid becoming a member of the royal family with their polygynous practices. Despite her objections, her father arranges the marriage, leaving Lidi desperate for a solution.
In a bold move, Lidi decides to forfeit her virginity, the only prerequisite for becoming the crown princess. She attends an undercover masquerade ball in a disguise and encounters a mysterious man with dark hair. After becoming intimate with him, she returns home, thinking that her plan has been successful. Unfortunately, the man she slept with is none other than the crown prince, and he is determined to have her all to himself!
