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. Can our heroes also help Hesperia make Shadybug and Claw Noir better people?

Marinette, now Chronobug, and Bunnyx must save the future by resolving the mystery of who dicovered Marinette's identity as Ladybug, when, and hhow they stole her Miraculous. Throughout the adventure, they learn that the Butterfly Miraculous has a new holder, the one who unraveled the ultimate secret. Ladybug's only hope is to defeat her opponent to prevent the end of Ladybug