Against the background of modern Paris, Marinete and Adrian, two very different high school students, were chosen to save Paris against the dark conspiracy in the city. Their main task is to hunt down akumas, a creature that turns normal people into criminals with super powers. Marinete can be transformed into a ladybug; Adrian, on the other hand, can turn into cat black.

They don't know each other's true identity, and Marinette doesn't know that Cat Noir is Adrien she secretly loves. Similarly, Adrian didn't know that Ladybug was a girl in her class.