Marinette, now Chronobug, and Bunnyx must save the future by resolving the mystery of who dicovered Marinette's identity as Ladybug, when, and how 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.