Principal Damocles starts cosplaying his favorite hero, Knightowl, and tries to act like him in real life as well. However, he becomes the laughing stock of Paris when his heroic exploits go horribly wrong and accidentally reveals his identity from his heroes. Humiliated, Damocles is akumatized by Hawk Moth and transforms into "Dark Owl", who has real superhero powers. Dark Owl manages to trap Ladybug and Cat Noir in a chamber where they will drown unless they hand over their Miraculouses, which would also mean revealing to each other their true identities. With Ladybug not ready to know that yet, they de-transform with their eyes closed, unaware that Tikki and Plagg see not only each other but also learn the identity of the other's owner. The two kwamis feed each other, so Marinette and Adrien can regain their powers, while they trick Dark Owl and Hawk Moth by giving them fake Miraculouses made out of salt dough. Ladybug and Cat Noir eventually defeat the owl-themed supervillain, and then help Mr. Damocles to become a superhero on a smaller scale by doing good deeds.