Acting on Fujiko's tip, Lupin and Jigen embark on an underwater adventure in Kiritappu to uncover a legendary treasure rumored to enable time travel. Evading authorities, the Lupin crew encounters Kyousuke Mamoh, a peculiar individual who transports them centuries back in time. Stranded in a historical feud between two tribes, Lupin, his comrades, and the tenacious Inspector Zenigata must swiftly decipher the treasure's enigma to prevent Mamoh from erasing Fujiko's lineage and altering the course of time.