Part 1

A newly discovered gem which is about to be soon exposed at Le Louvre in Paris bring the attention of the infamous magician thief Kaito Kid, making it his target for his next heist.

Meanwhile, Kaito and Aoko travel to Paris for a students exchange program, they are placed in Bustier's class where they befriend a girl called Marinette but also clash with the rest of the class lead by the liar Lila Rossi.
From there came chains of event leading to the akumatization of one of them.

How Ladybug and Chat Noir will handle Kaito Kid and this new akuma?