Oblivio's defeat has gotten the two powerful superheroes of Paris, wondering what went down during that faithful night.
The young Ladybug feels like she betrayed Adrien Agreste with that kiss she has with Chat Noir, even though she knows that Adrien would never in a million years fall for her civilian self as Marinette Dupain-Cheng. She told herself that the kiss was most likely to help save Chat Noir, as she did once with Dark Cupid situation. Marinette would never admit to herself, but in the back of her mind, she knew there was something much more to the whole situation.
The flirtatious Chat Noir was more than happy when he saw that picture of himself and Ladybug kissing. That one picture ended up giving him many thoughts about trying to win his lady over once and for all. If he could do it once, then he could clearly get those feelings to return but he doesn't know how to go about this situation. Adrien made the photo as his screensaver in hopes it would jog his memory of the events of that day, he knows deep down it's a lost cause because of the ladybug miraculous, changing everything back to the way it was.
Ever since that faithful day went down Ladybug started to feel like there was something familiar with Chat Noir, and Andrien started to feel the same familiar feeling with Marinette. That feeling of familiarity was trying to tell both teens that they knew more about each other, but everything seems completely the same after the defeat of Oblivio.