Padudu hails from the aquatic realm of Sea Heaven, journeying to Earth to become a magical girl. She wears Uokichi, a sentient fish serving as her cloak, source of sustenance, and magical focus; she frequently consumes portions of him despite his visible distress.

Her quest starts when chosen to represent her town in Sweetland's coliseum. Traveling there, she is swept into Dance Valley and imprisoned by Mayor Koffy. In the dungeon, she meets Nonononn, a fugitive witch also from Sea Heaven, and they form an alliance to escape. Later, Padudu accidentally interrupts a duel between Pipin and another candidate, falling on Pipin after her victory. This awards Padudu a Hanamaru stamp and sparks Pipin's declaration of lifelong rivalry. Despite this initial conflict, they develop a cooperative relationship. The duo then encounters MyuMyu, an older candidate who joins them while hiding her manipulative ambitions.

Padudu possesses a dimwitted yet determined personality, often forgetting her own capabilities like Uokichi's flight power, leading to preventable mishaps. Her optimism and desire for friendship persist even toward antagonists like Nonononn, whose actions frequently cause Padudu's false arrests by officers Ketchup and Mustard. Key events involve participating in absurd contests—territory defense, eating competitions, wish-granting—to earn Hanamaru stamps. One wish-granting endeavor inadvertently causes a global nuclear catastrophe, though Padudu remains unaware of the consequences.

In the 3D OVA, Padudu is captured and jailed alongside Nonononn in Dance Valley. Forced into combat by jailer Cofy and her panther Panpan, they kill Panpan, leading to Cofy's demise. The OVA concludes without resolution, hinting at ongoing conflict with Queen Purilun. Her story ends without achieving her goal, as the series lacks a definitive conclusion regarding her collection of Hanamaru stamps or ascension as a full magical girl.