Miraculous holders from another world appear in Paris. They come from a parallel universe where everything is reversed: the holders of Ladybug and Black Cat Miraculouses, Shadybug and Claw Noir, are the bad guys, and the holder of the Butterfly Miraculous, Hesperia, is a superhero. Ladybug and Cat Noir will have to help Hesperia counter the attacks of their evil doubles and prevent them from seizing the Butterfly's Miraculous.