Julia, daughter of Douglas—a wealthy American presidential candidate—is drawn into a deadly conflict with a cult obsessed with fulfilling Nostradamus’ prophecies. During a flight, she steals a doll concealing a diamond hidden by Lupin III, sparking a perilous chain of events that culminates in her kidnapping by the cult. Their goal: force Douglas to abandon his campaign and surrender a lost volume of Nostradamus’ predictions locked in his high-security vault.

Fujiko Mine, undercover as Julia’s chaperone, exploits Julia’s connection to infiltrate the vault. Despite repeated abductions by the cult’s operatives, Julia proves resourceful, severing a hypnotic wristband controlling Fujiko to reclaim her memories and thwart the cult’s schemes. Her alliances with Lupin and his crew shift fluidly, oscillating between pawn in their gambits and proactive participant in unraveling the conspiracy.

In the final confrontation, Julia hands Lupin the recovered prophecies, later defacing the book with irreverent doodles that strip it of value. This sabotage inadvertently cripples the cult’s leverage, dismantling their apocalyptic agenda. Post-crisis, she quietly returns the stolen diamond to Lupin and reunites with her family, her role in the ordeal concluded.