In the world of PriPara, a magical amusement park accessible through a special PriTicket, girls transform into dazzling idols to perform in daily auditions broadcast across the globe. For Laala Manaka, a loud and cheerful fifth grader, this world seems out of reach because her school, Paprika Private Academy, strictly forbids elementary students from participating in idol activities. Laala initially only wants to watch the shows, but a chance encounter when she returns a lost PriTicket to the cool and rule-abiding idol Mirei Minami accidentally leads to her own unexpected debut.

Once inside, Laala discovers a place where she can finally be herself. Teaming up with Mirei and the enigmatic top idol Sophy Hojo, who has two distinct personalities triggered by eating pickled plums, Laala forms the idol unit SoLaMi Smile managed by a bear named Kuma. Their rivals include the group Dressing Pafé, composed of the serious "Go" prodigy Sion Todo and the Canadian-Japanese twin sisters Dorothy and Reona West, managed by a rabbit named Usagi. The narrative follows Laala and her friends as they compete in grand prix tournaments, aiming to earn legendary costumes like the Paradise Coord. A key early conflict involves the robotic vocal doll Falulu, a being created from the dreams of girls who cannot enter PriPara, whom Laala and the combined unit SoLaMi Dressing must revive after a competition goes wrong.

The story expands in the second season with the opening of the Dream Theater and the Dream Idol Grand Prix, where idols compete in teams of five. New characters include the angel-devil duo Aromageddon, the energetic Fuwari Midorikaze, and the art teacher Ajimi Kiki. A major antagonist emerges in Hibiki Shikyoin, the Masked Genius, who temporarily takes control of PriPara and transforms it into the restrictive CelePara, forcing the idols to perform in an underground theater. This season also introduces the mischievous vocal doll Gaaruru, who joins Aromageddon to form Gaarmageddon.

The third and final season centers on the Divine Idol Grand Prix. A giant UFO appears over the town, and Laala discovers a mysterious baby named Jewlulu who calls her Mama. It is revealed that the baby is actually the missing divine judge Jewlie, and the idols are tasked with raising her to unlock their true potential. This season features new rivals like the virtual trio TRiANGLE, which hides a shocking secret, and the formation of the unit NonSugar. The series culminates in a final concert where the system fails, and the idols must use the power of their friendships to save the PriPara world and revive Jewlie.