Marinette is formally introduced to Master Fu, whom she knew as Tikki's healer, learning that the man is the last Miraculous Guardian due to a past mistake he made that destroyed his temple with the Butterfly and Peacock Miraculouses lost in the chaos. Fu reveals the book Marinette brought to be a spell book covering Miraculouses, suspecting its owner could be Hawk Moth, with Marinette fearing Adrien could be the masked figure. But she learns from her classmates that the book belonged to Adrien's father Gabriel, who prevent Adrien from going to school for losing the book. Marinette heads to the Agreste estate as Ladybug, finding out that Gabriel had been akumatized into "The Collector", a supervillain with the ability of trapping anything that touches the pages of his blank sketchbook. After Ladybug and Cat Noir eventually defeat and restore Gabriel, Marinette and Fu concludes that he cannot be Hawk Moth. Fu copies the book's contents onto a smartphone before Marinette returns it to Gabriel, admitting that she was the one who held the book, not Adrien. Gabriel reveals that he obtained the book while visiting Tibet and that it is a memento of his wife, rescinding Adrien's grounding as he returns to school to the joy of his classmates. But Gabriel is revealed to have copied the book along with being Hawk Moth, having akumatized himself as a ploy to cover his tracks.