Heroes' Day - Part 1 - Catalyst.It is Heroes' Day and the anniversary of heroic activities. Gabriel is tired of the times he failed to keep his promise, and Nathalie suggests they should implement their biggest plan and target Lila Rossi to re-akumatize her. Lila is broadcasting herself to Collège Françoise-Dupont about being invited to hang out with Prince Ali, except Marinette and Adrien are doubtful of this. While everyone is giving a speech about their good deeds, Marinette feels disappointed because she hasn't prepared hers yet and ends up stretching the truth to her entire class. Gabriel pays homage to Ladybug and arouses Lila's frustration to akumatize her into Volpina again. Volpina creates an illusion of an akumatized version of Ladybug killing Cat Noir during the Heroes Day Parade in order to render the Parisians vulnerable to emotions. Hawk Moth retrieves the akuma and gives it to Nathalie, transforming her into "Catalyst", with the enhancement to increase his abilities with scarlet akumas to create his own army. Overwhelmed by the akumatization of previous villains, Ladybug immediately goes to Master Fu after de-evilizing Vanisher, and gives both the Turtle and Fox Miraculouses to Nino and Alya, despite revealing their secret identities, while Cat Noir gives the Bee Miraculous back to Chloé. Scarlet Moth makes his very first public appearance at the Eiffel Tower, and Ladybug, Cat Noir, Rena Rouge, Carapace, and Queen Bee arrive at a lookout and begin to try to come up with a strategy.