Secretly using his cruiser as a floating casino, California mafia don Lukino Marcano is still hunting for a gold‑laden shipwreck that could rival the budget of a small country. Lupin spots the plan to recover the long‑lost treasure and enlists his partners, Jigen, Goemon, and Fujiko, to infiltrate Lukino’s lavish party. As always, Inspector Zenigata trails Lupin, and this time he’s teamed up with an unusually aggressive local cop. Together, they uncover the true mystery behind Alcatraz Island’s prison and the sinister syndicate known as the Secret Seven.