In the lively city of Townsville, chaos unfolds as a mischievous monkey named Jojo and a hillbilly known as Fuzzy Lumpkins wreak havoc. To combat the turmoil, Professor Utonium combines Sugar, Spice, and Everything Nice in a cauldron, only to mistakenly add some Chemical X. Miraculously, he still succeeds in creating three extraordinary girls: Blossom, the determined leader; Buttercup, the feistiest fighter; and Bubbles, the sweet and gentle spirit. The bond between the girls and the Professor grows strong as they share typical family moments together.
As they begin their school adventures, the girls discover the concept of tag, only to have their playful game escalate out of control. Using their powers, they end up causing substantial damage in the city. That evening, the Professor warns them against displaying their abilities in public. Regrettably, their reckless behavior leads the citizens to view them as outcasts, and the Professor finds himself incarcerated. The girls, determined to return home, wander into an unfamiliar alley, where they confront a gang of bullies known as the Ganggreen Gang. Their troubles are alleviated when Jojo comes to their rescue.
Feeling overshadowed by the girls’ favor with the Professor, Jojo harbors resentment but also reveals his own struggles with his powers, sparking empathy in the trio. He then cunningly convinces them to help him construct a laboratory and a machine, claiming it will "improve the city." Once the project is complete, Jojo treats the girls to a trip to the zoo, but his real intention becomes sinister as he installs a transportation device on the primates. He teleports these primates to his lab and, with the help of Chemical X, turns them into malicious mutants.
The next day, the Professor is released, only to be met with the harsh reality that Jojo, now calling himself Mojo Jojo, is terrorizing the city with his primates. Blaming the girls for his villainy, Mojo further tarnishes their reputation, leading the Professor to feel disappointed and losing faith in them. The girls, feeling downcast, retreat to outer space, pondering their failures on an asteroid.
Mojo declares his ambition to rule the world, but his primate minions have their own chaotic schemes to unleash on Townsville. Hearing the commotion, the girls rush back to help. Buttercup bravely defeats a colossal ape, while Blossom and Bubbles realize they must harness their powers for the good of their town. The trio bands together to thwart all of Mojo's minions. Yet, Mojo overdoses on Chemical X, transforming into a massive monster, cornering the girls. He offers an alliance to conquer the world, but they resolutely reject him, pushing him from a towering skyscraper.
Just then, the Professor arrives with Antidote X, which shrinks Mojo back to his original size, leading to his arrest by the police. The girls contemplate using the antidote to relinquish their powers and revert to "normal" little girls. However, the townsfolk, having witnessed their true natures, apologize for their earlier misjudgment and encourage the girls to retain their abilities. The Mayor requests that they use their powers to protect Townsville from villains and threats. With the Professor's approval, they form their own crime-fighting team, proudly named The Powerpuff Girls.
