"Princess Knight Catue" is a fantasy anime series centered around Catue, a young princess who disguises herself as a knight to protect her kingdom from external threats and internal corruption. The story unfolds in the fictional kingdom of Liones, where Catue, despite her royal lineage, trains rigorously in swordsmanship and combat. Her dual identity as both a princess and a knight allows her to navigate the complexities of court politics while actively defending her people.

The narrative begins with the kingdom facing an invasion from a neighboring empire seeking to exploit Liones' resources. Catue, determined to prove her worth beyond her royal title, takes up arms under the guise of a male knight. Her journey is marked by battles, alliances, and the gradual revelation of a deeper conspiracy involving traitors within the royal court. As Catue uncovers the truth, she must balance her duties as a protector with the expectations placed upon her as a princess.

Key characters include Catue's loyal squire, Ryn, who aids her in maintaining her secret identity, and Lord Garrick, a cunning nobleman whose ambitions threaten the stability of the kingdom. The series also introduces a rival knight, Sir Alaric, whose initial antagonism toward Catue evolves into mutual respect as they join forces against common enemies. Themes of loyalty, identity, and the struggle for justice are woven throughout the narrative, with Catue's growth as a leader and warrior serving as the central focus.

The plot is driven by a mix of political intrigue, action-packed battles, and moments of personal reflection, as Catue grapples with the weight of her responsibilities. The series explores the challenges of maintaining a dual identity in a world where gender roles are rigidly defined, while also highlighting the importance of courage and integrity in the face of adversity. Through its episodic structure, "Princess Knight Catue" builds toward a climactic confrontation that tests Catue's resolve and reshapes the future of her kingdom.