After Chat Noir finds out Ladybug likes someone else, he accidentally ends up spooking his easily frightened classmate, Marinette Dupain-Cheng. To ask for forgiveness, he sends her a card to say sorry. She writes one back. It soon turns into a nightly routine of exchanging letters. He starts to realize that his love for Ladybug is starting to hurt less and less everyday because of this brave and shy girl. Who could have thought that it all started with her smiling and singing to some stargazers.