The notorious master thief Lupin Sansei returns to his thieving ways in San Marino, Italy, but this time his target seems to be love itself. To everyone's surprise, Lupin ends up marrying the famous heiress and businesswoman Rebecca Rossellini, leaving his gang and Interpol Inspector Zenigata Kouichi bewildered. As questions arise about Lupin's true intentions, his loyal companions Jigen Daisuke and Ishikawa Goemon wonder if there's more to this romantic escapade than meets the eye. Amidst the chaos, it becomes clear that Lupin is not the only cunning thief in San Marino, with a mysterious MI6 agent named Nyx adding another layer of intrigue to the mix. With mysteries abound, what twists and turns await Lupin in this unpredictable Italian escapade?