"Once Upon A Time In China" is an anime series that adapts the classic tale of Wong Fei-hung, a legendary Chinese martial artist, physician, and folk hero. Set in late 19th-century China during the Qing Dynasty, the story unfolds against a backdrop of political turmoil, foreign imperialism, and cultural upheaval. Wong Fei-hung, a skilled martial artist and compassionate healer, operates a clinic in Foshan, Guangdong Province, where he treats the sick and trains disciples in martial arts. His unwavering sense of justice and dedication to preserving Chinese traditions make him a respected figure in his community.

The narrative explores Wong Fei-hung's struggles to protect his people from both internal corruption and external threats. Foreign powers, particularly Western colonial forces, exploit China's weakening government, leading to widespread unrest. Wong Fei-hung frequently clashes with corrupt officials, local gangsters, and foreign mercenaries who seek to undermine Chinese sovereignty. His martial arts prowess, rooted in the Hung Ga style, becomes a symbol of resistance and national pride. Alongside his loyal disciples, including the spirited Leung Foon and the resourceful Bucktooth So, Wong Fei-hung navigates a series of challenges that test his skills, principles, and resolve.

The series delves into themes of cultural identity, loyalty, and the clash between tradition and modernity. Wong Fei-hung's interactions with foreign characters, such as the well-meaning but culturally ignorant Westerners, highlight the complexities of cross-cultural exchange during this period. The story also introduces romantic subplots, particularly Wong Fei-hung's relationship with Aunt Yee, a progressive and independent woman who represents the changing role of women in society. Through its episodic structure, the series balances action-packed martial arts sequences with moments of introspection and social commentary, offering a nuanced portrayal of a pivotal era in Chinese history.