Internationally famous thief, Arsene Lupin the Third, receives half of the large diamond known as Twilight from old crimeboss Doruune. Doruune tells him that if he finds the other half of the diamond in Morocco, they will lead him to treasure. Lupin and his gang (Daisuke Jigen, Goemon Ishikawa, and Fujiko Mine) head to Morocco, but get caught up in the middle of a conflict between the government and Gelt rebels. Both sides want Lupin, but no one wants him more than his 'old friend' Interpol Inspector Kouichi Zenigata, who has pursued him to Morocco...