In the lively town of Kasukabe, Shinnosuke's father finds himself staring at the television, which broadcasts a rather peculiar story about a man who, after enjoying a bowl of ramen, spirals into a fit of rage. Meanwhile, at school, during the preparations for the annual sports day dance, Shinnosuke and his friends witness their classmate, Masao Satou, being bullied by two notorious students, Hitoshi and Terenobou. Contrary to his usual tearful demeanor, Masao surprises everyone by exhibiting newfound confidence and strength that enables him to stand up for himself.
Curious about Masao’s transformation, Shinnosuke and his friends decide to follow him. They track him down to a bustling Chinatown, where they find Masao honing his skills by balancing a water bowl atop his head. When Shinnosuke calls out to him, Masao reveals that he is training in a Chinese martial art known as Kung Fu. Soon, they encounter a Kung Fu master and his star pupil, Ran chan. The master, impressed with Shinnosuke's enthusiasm, invites him to learn the martial art as well.
Suddenly, their training is interrupted by thugs from the Black Panda ramen shop who demand ownership of their land. The Kung Fu master courageously faces off against these thugs and defeats them with ease, prompting the children to commit to their martial arts training. The following day, they delve into the legendary Kung Fu technique known as the Punni-Punni flow. According to lore, an anonymous martial artist once mastered nine levels of Kung Fu, gaining incredible power from the Punni-Punni mainland and stopping a catastrophic war in the process. The teacher informs the kids that to reach the mainland alongside Ran chan, they must complete these nine rigorous steps.
As the days pass, Shinnosuke rapidly progresses through the levels, a stark contrast to Masao, who struggles even at the first level. Meanwhile, the antagonists from the Black Panda ramen continue to create chaos. The malevolent leader, Don Panpan, confronts the Kung Fu master, rendering him incapable of defending himself and causing him to sporadically utter nonsensical phrases like “panties to look.”
Upon returning to Chinatown, the group finds most of the locals have fled due to the terror instigated by the Black Panda ramen crew. Unbeknownst to them, Shinnosuke's agile younger sister, Himawari, consumes some Black Panda ramen, transforming her into an enraged creature, complete with dark circles under her eyes reminiscent of a panda. Desperate to save Himawari, Shinnosuke and his friends infiltrate the Black Panda ramen factory in search of an antidote. They document their findings with Kazama's phone, but their stealth is compromised when Masao, due to his rigid movements, accidentally reveals their mission.
In a desperate bargain, Kazama agrees to trade the phone for Masao's safety. Just when all seems lost, Ran chan appears to rescue them from the clutches of danger, guiding them back to Shinnosuke's home. There, Shinnosuke masterfully completes all levels of Kung Fu, making him eligible to join Ran chan on their journey to the Punni-Punni mainland, which lies in China. However, Masao grapples with feelings of inadequacy and, believing he has no skills to contribute, tearsfully opts out of the journey.
Their adventure takes a dramatic turn when they face off against the Black Panda ramen's minions, including the Nohara family's neighbors who have been coerced into servitude. In their escape, the master sacrifices himself for the children's safety, solidifying Ran chan’s determination to seek out the magic in the Punni-Punni mainland. Thus, they travel to China, leaving behind only Shinnosuke's friends.
Upon arrival, they find the mystical region and encounter the Punni-Punni fairy who poses a series of questions. In a surprising turn of events, Shinnosuke triumphs in answering, whereas Ran chan falls short. The fairy explains that due to her lack of a gentle spirit, Ran chan will be unable to handle the magic’s strength. However, when faced with a choice, Shinnosuke refuses to consume the potion meant for power, while Ran chan succumbs to temptation and drinks it instead.
The pair returns to Kasukabe, ready to take on Don Panpan. However, Ran chan becomes corrupted by the magic, morphing into a being that can enforce peace yet embodies a malevolent demeanor, leading to turmoil in the town. In a bid to reclaim their friend, Shinnosuke and his allies join forces with Masao to form the Kasukabe Defense Group, employing their new Jenkaa dance technique to unite everyone back to their true selves.
Lady fortune smiles as their dance reverses the enchantment, restoring Ran chan and bringing peace back to Kasukabe. Following her transformation, Ran chan sets off on an adventure around the world on the master’s commands, while the children bid her a heartfelt farewell. The movie concludes on an uplifting note, reinforced by a song that recaps the entire epic journey they undertook.
