Trouble occurs simultaneously in the worlds of "Aikatsu!." and "PriPara," distorting space-time and connecting the two worlds. The idols from Starlight Academy and Parajuku enjoy a dream collaboration at a joint live festival, but strange things start happening one after another, such as Manaka Lala's family restaurant, "Papa's Pasta," changing to "Papa's Chinese," and the Starlight Academy dormitory where Ozora Akari and her friends live becoming smaller. Realizing that they may be able to return the world to its original state if they pool their "idol brilliance," the girls decide to join forces. With the paths they have each walked and the feelings they have accumulated in their hearts, they all strive to put on the best live show possible.