Count Cagliostro is voiced by Tarō Ishida in the original Japanese version of the film. In the Streamline English dub he is voiced by Michael McConnohie and in the Manga Entertainment dub he is voiced by Kirk Thornton.
Count Cagliostro is made aware of Clarisse's attempt to escape and how she was aided by the master thief, Arsène Lupin III. The Count dispatches his assassins to deal with Lupin, but the wiley thief eludes them and later makes plans to break into the Count's castle, both to save Clarisse and to confirm that the Count is responsible for producing the "goat bills" he swindled from a casino in Monaco. Lupin also arranges for his arch-nemesis, Inspector Koichi Zenigata, to arrive in the country. While Zenigata thinks he's only after Lupin, Lupin plans to reveal the Count's criminal activities to him. While investigating the castle, Zenigata falls for one of the many traps within and falls down into the sewers beneath the castle. Lupin later joins him after failing to rescue Clarisse.
Even though Lupin and Zenigata manage to escape from the sewers, Count Cagliostro still prevents them from rescuing Clarisse and reacquires Clarisse's signet ring. Lupin and Zenigata manage to escape the castle alive but Lupin is severely wounded. He is saved by his cohorts Jigen and Goemon who take him to safety, but he is too weak to make another attempt to save Clarisse before her wedding. However, on the day of the wedding, Lupin, along with Jigen, Goemon and Fujiko Mine, infiltrate the wedding and attempt to expose the Count's crimes before the entire world since the ceremony is being broadcast on live television. A fight ensues between the Count's soldiers and Lupin's friends as well as Zenigata's men while Lupin and Clarisse flee with the Count in hot pursuit.
Lupin and Clarisse are cornered on the outside of the castle's clock tower as the Count closes in. Lupin tries to deal with the Count, giving him both the signet rings in exchange for Clarisse's freedom. The Count is able to take the rings anyway and Lupin and Clarisse fall from the clock face and into the lake below. Count Cagliostro then inserts the two rings into a small recess on the clock face which activates a mechanism that will supposedly reveal the hidden treasure of Cagliostro. The treasure is revealed, but the Count never gets to see it. When the mechanism was activated, the hands of the clock quickly moved to 12 o'clock and the Count was crushed between the hands.
When the Count dies, the clock tower is seen from a distance so the gory details are not displayed.