Lupin and company are after the Bell of the Duchy of Beltenberg, constructed in the 15th century. However, it's a fake, and it's being guarded by Zenigata. Angered at these various problems, Fujiko takes off for Paris, where she falls in love with, and becomes engaged to, Claude, heir to the duchy. She has a weakness for royalty, after all. But the aim of the rulers is to exchange Fujiko for discovery of the real bell.