"Koihime Musō" is a historical fantasy anime series that reimagines the events of the Chinese classic "Romance of the Three Kingdoms" with a gender-swapped cast. The story is set in a fictionalized version of ancient China, where the land is plagued by corruption and chaos. The central protagonist, Kan'u Unchou, is a young woman with a strong sense of justice and exceptional martial prowess. After her village is destroyed by bandits, she embarks on a journey to restore peace and protect the innocent. Along the way, she encounters other skilled warriors, including her sworn sister, Chouhi Yokutoku, and the intelligent strategist, Bachou Mouki. Together, they form a bond and vow to fight against tyranny.

The narrative unfolds as Kan'u and her companions gather allies and confront various warlords and factions vying for control of the land. Among these adversaries is the ambitious and cunning Ryuubi Gentoku, who seeks to unite the country under her rule. The series explores themes of loyalty, camaraderie, and the moral complexities of leadership and warfare. As the group grows, they face numerous challenges, including battles, political intrigue, and personal dilemmas, all while striving to uphold their ideals in a turbulent world.

The anime blends action, humor, and lighthearted moments with its historical and dramatic elements. The characters are drawn from the "Romance of the Three Kingdoms" lore but are reimagined with distinct personalities and relationships, adding a fresh perspective to the familiar tale. The story progresses through episodic arcs, each focusing on different conflicts and character developments, ultimately building toward a larger narrative of unity and resistance against oppression. The series maintains a balance between its adventurous tone and the emotional depth of its characters, offering a unique take on a classic historical setting.