Inspector Zenigata arrives in San Marino after receiving a note from Lupin The Third. This time, instead of a declaration of a new theft, it's a wedding invitation. It seems Lupin is getting married to Rebecca Rossellini, the young Chair of the Rossellini Zaibatsu. But behind the wedding is Lupin's true goal: to steal San Marino's national treasure, the Royal Crown of Libertas. Somehow, Zenigata receives a false note from someone who isn't Lupin, which clues him in to Lupin's plan. Who sent him the note, and why?