After battling a group of highly trained assassins, the suave thief Lupin III and his loyal friends receive a mysterious invitation to a mysterious island. Their plane is unexpectedly shot down, leaving them stranded and targeted by the island's residents, former foes, and a terrifying immortal creature called Muom, who aims to obliterate Lupin's legacy. As a perilous toxic fog envelops them, Lupin is forced to face his most formidable adversary in an adventure more audacious than any he has ever undertaken.