Ever since Natalya was young she wanted to follow in her brother's footsteps and hunt vampires. The year is 1889 and Natalya gets the chance of a lifetime when her brother Ivan goes missing after a werewolf attack on his group of hunters. She sets out with Arthur, the local banker's son, and Lovino, a coach driver, to find him.

Kiku (Ladybug) and Arthur (Cat Noir) are now a couple, but that doesn't mean their troubles are over. Hawkmoth is still at large, Arthur's mother is still missing, and Gilbert might be the only one with working brain cells when it comes to finding out our heroes' identities. Secrets will be revealed and relationships will be tested.