"Koihime" is an anime series that blends historical fiction with romantic and comedic elements, set in a reimagined version of China's Three Kingdoms period. The narrative centers on a young girl named Kan'u Unchou, who embarks on a journey to restore peace to the land after her village is destroyed by bandits. Kan'u is joined by her childhood friend, Chouhi Yokutoku, and later by other female warriors, each inspired by historical figures from the Three Kingdoms era. Together, they form a group dedicated to fighting tyranny and injustice.

The story unfolds as Kan'u and her companions encounter various factions and leaders vying for control of the fractured land. Among these is the ambitious and cunning Ryuubi Gentoku, who seeks to unite the territories under her rule. The series explores themes of loyalty, friendship, and the moral complexities of leadership, as the characters navigate alliances, betrayals, and personal growth.

Key characters include Kan'u, portrayed as a determined and idealistic warrior with a strong sense of justice; Chouhi, her loyal but often impulsive friend; and Ryuubi, a strategic and charismatic leader with a vision for a unified empire. Other notable figures include Bachou Mouki, a fierce and independent fighter, and Kada, a mysterious and skilled assassin with her own motivations. The interactions between these characters drive much of the plot, as they face both external conflicts and internal struggles.

The series incorporates lighthearted moments and comedic elements, often through the playful dynamics between the characters, while also addressing the harsh realities of war and the sacrifices required to achieve peace. The narrative balances action-packed battles with quieter, character-driven scenes, providing a multifaceted exploration of its historical and thematic foundations.