"Ranma ½: Big Trouble in Nekonron, China" is a feature-length anime film based on Rumiko Takahashi's popular manga series "Ranma ½." The story centers on Ranma Saotome, a martial artist cursed to transform into a girl when splashed with cold water, and his fiancée Akane Tendo. The narrative begins when a mysterious flying fortress arrives in Nerima, kidnapping Akane and her sister Kasumi. The fortress belongs to Prince Kirin, a ruler from the distant land of Nekonron, China, who seeks to marry Akane as part of a ritual to restore his kingdom's prosperity.

Ranma, along with his father Genma, Akane's father Soun, and several friends, pursues the fortress to Nekonron. Upon arrival, they discover that Prince Kirin's intentions are tied to an ancient prophecy involving the "Dragon's Whisker," a magical artifact that can grant immense power. Akane is chosen as the "Maiden of the Spring," a key figure in the ritual, but her refusal to cooperate threatens the kingdom's stability. The group learns that the ritual is not merely ceremonial but involves a dangerous battle against the "Phoenix People," a group of powerful warriors who oppose Kirin's rule.

As the story unfolds, Ranma and his companions face numerous challenges, including battles with the Phoenix People and navigating the cultural and magical peculiarities of Nekonron. The film incorporates the series' signature blend of martial arts, comedy, and supernatural elements, with Ranma's gender-swapping curse playing a recurring role in both action and humor. The climax involves a large-scale confrontation where Ranma must use his martial arts skills and ingenuity to rescue Akane and thwart Kirin's plans, ultimately revealing the true nature of the Dragon's Whisker and its connection to the kingdom's fate.

The film maintains the core dynamics of the "Ranma ½" series, with its ensemble cast of characters, including the rivalries and comedic misunderstandings that define their relationships. It expands the series' world-building by introducing the fantastical setting of Nekonron and its unique mythology, while staying true to the humor and action that fans of the franchise expect.