A story of how two rival thieves, Lupin III and Fujiko Mine, first met each other while trying to steal the same thing.
Fujiko is engaged to be wed to a cult leader named Fraulein Hoyle, who has his own little island compound somewhere near India. However, Fujiko tries to drug him and use him to find the secret of the self-named drug he uses to control his followers. Lupin III watches nearby and tries to cut in on the action, but the cult leader immediately wakes up and imprisons them both, with plans to execute both Lupin and Fujiko together.
While locked in a cell, Fujiko and Lupin challenge each other to steal the drug first, but Fujiko quickly acts by having Lupin moved to a different cell. The next day, the cult leader executes them both, only to find that both thieves have replaced their own bodies with doubles at the execution. Lupin and Fujiko quickly escape, but then find their own way into a secret chamber to recover the source of the drug. After a brief fight with each other, Lupin reveals another trick, that he sent a note to Inspector Zenigata daring him to come find him within the Fraulein Hoyle cult.
Zenigata heads to the island with a large force of policemen in tow, just as the cult leader tries to blow up his own secret chamber with Lupin and Fujiko inside. They capture the cult leader and try to arrest the surrounding cultists as well. Fujiko and Lupin each manage to escape to the ocean, but upon contact with the water, the pure drug washes off and becomes useless.
Later, as Fujiko heads off on a motorbike, she notices a message hidden by her left thigh: Lupin III swears that he will steal her heart as she drives away.