This is a prequel to the series. The story goes back to when Gabriel and Emilie first find the miraculous and ends somewhere around the end of the fourth season.
*Takes place at the beginning of Weredad, and makes new timeline*
After Marinette pretends to confess her love, the Parisian hero, Cat Noir finds new feelings for the girl. He works to get through and find them. Unless... They were already there?
(I do not own "Miraculous: Tales of Ladybug & Cat Noir", or any of its characters.)