Zenigata boards the vessel 'Machine Gun Kelly', a floating casino under mafia control, to thwart Lupin's heist scheme targeting the casino's funds. Despite Lupin's crew breaching the vault, their getaway is foiled by Zenigata's gunfire. Unbeknownst to many, the ship harbors a hidden agenda known to Lupin – a quest for a sunken treasure ship laden with gold. In a cunning move, Lupin secures vital information about this expedition. Now, amidst evading Zenigata, battling the mafia, and confronting a clandestine group headquartered beneath Alcatraz, Lupin and his team delve into the enigmatic organization and the mystery shrouding the submerged riches.