The film takes place on Aiai Island, a mysterious tropical location that becomes the stage for the Super Miracle Idol Festival, advertised as the number one idol event in the universe. Uta Sakura and her fellow Idol Precure members are invited to perform at the festival by Totto, a coral fairy who serves as the event's organizing committee chairman. The festival features a diverse lineup of performers, including animal and robot idols, creating a grand and lively atmosphere.

The festive mood is shattered when a mysterious monster suddenly appears, plunging both Aiai Island and the wider world into a dire crisis. In a surprising turn of events, the girls are transported back in time, adding a layer of mystery to their predicament. The key to resolving this crisis appears to be linked to two figures: Tera, a red-haired girl who despises idols and holds knowledge of the island's secrets, and the legend of Amasu, a goddess who is said to protect the island from disaster. A statue of this goddess, supposedly her petrified form, stands on the island and is central to the unfolding mystery.

As the Idol Precure team works to uncover these secrets and save the day, they are joined by the Pretty Cure teams from the two previous series, Wonderful Precure! and Hirogaru Sky! Precure. This crossover brings together the main characters from those seasons, including Cure Wonderful and Cure Friendy from the former, and Cure Sky and Cure Prism from the latter, to help face the threat.

The main characters driving the story are the five Idol Precure members. The group is led by Uta Sakura, also known as Cure Idol, a spirited second-year middle school student who loves to sing. Her friends and fellow Cures are Nana Aokaze, the intelligent pianist who transforms into Cure Wink; Kokoro Shigure, the passionate dancer who becomes Cure Kyun-Kyun; and the fairies Purirun and Meroron, who can transform into Cure Zekyoon and Cure Kiss, respectively. Together, they must use the power of their songs and performances to combat the monsters, unravel the legend of Aiai Island, and deliver a kirakkilive performance that can save the world.