Lupin III: The Plot of the Fuma Clan (ルパン三世 風魔一族の陰謀 Rupan Sansei: Fūma Ichizoku no Inbō?), released in North America as Rupan III: The Fuma Conspiracy, is Arsène Lupin III's first direct-to-video adventure, and the first Lupin adventure since the pilot to not feature Yasuo Yamada (due to a tight budget) as Lupin. Instead, Lupin's voice is provided by Toshio Furukawa. It is also the only Lupin title not to feature Kiyoshi Kobayashi as Jigen.
The movie begins at the wedding of Goemon Ishikawa XIII and his fiancée Murasaki. During the ceremony where the Suminawa family heirloom, a valuable antique urn, is handed over to Goemon, several black-clad ninja attack the party and attempt to steal the urn. Lupin and his colleagues fight off the ninja, but during the confusion others kidnap Goemon's bride-to-be and escape, leaving a ransom note.
Meanwhile, Inspector Zenigata has retired to a Buddhist temple following the apparent death of his long-time quarry Lupin. A colleague from ICPO is trying to persuade him to return to work, but Zenigata says he has "no interest in a world without Lupin". Zenigata soon changes his mind when he is shown a photograph of Lupin at the wedding ceremony earlier that day. Zenigata resumes his life-long pursuit of Lupin!
At the Suminawa household, Murasaki's grandfather explains to Goemon that the urn holds the secret location of the Suminawa family treasure, and that the Fuma clan, the ninjas who attacked the ceremony that morning, have been trying to steal it for just as long. He refuses to hand over the urn to the Fuma clan, but Lupin steals it instead and exchanges it for Murasaki's life. The urn contains a hidden engraving revealing the location of the treasure; an underground cave deep in the mountains.
Soon the race is on as Lupin and company, with Zenigata in close pursuit, try to beat the Fuma clan in negotiating the trap-laden caves beneath the mountain to find the ancient treasure.
Due to budget concerns, TMS decided not to employ the regular voice cast for the OVA, instead going for a slightly less-expensive yet still well-known Aoni Production cast. When the news was broken to Yasuo Yamada, it was not made clear who was responsible for the dismissal, leaving him with the impression that Lupin III's creator, Monkey Punch, had lobbied the producers for a new voice actor. (In reality, Monkey Punch was happy with Yamada's portrayal, but felt that he had no business in telling the production company what to do.) Monkey Punch did try to reassure Yamada (who had developed a friendship with him over the years of Lupin III's run on TV) that he had nothing to do with it, and the regulars were reinstated with the first television special, Bye Bye Liberty Crisis. However, relations between Yamada and Monkey Punch were permanently strained by the affair. 
After being released on home video, Fuma Conspiracy was released in theaters as well. 
In the United States, Animeigo released The Fuma Conspiracy under the title "Rupan III: The Fuma Conspiracy," and referred to the title character as "Rupan" in the English dub and subtitle scripts. Licensor Toho demanded the change out of fear that the estate of Maurice Leblanc, creator of the original Arsene Lupin, would sue for the unauthorized use of the name. It has since been re-released by Discotek under the title "Lupin the 3rd: the Fuma Conspiracy".
- Toshio Furukawa as Arsene Lupin III, master thief
- Banjō Ginga as Daisuke Jigen
- Kaneto Shiozawa as Goemon Ishikawa XIII
- Mami Koyama as Fujiko Mine
- Seizō Katō as Inspector Koichi Zenigata
- Mayumi Shō as Murasaki
- Kōhei Miyauchi as Old Man Suminawa
- Shigeru Chiba as Inspector Fumi
- Masashi Hirose as Boss
- Shigeru Nakahara as Gakusha
- Robin Robertson as Lupin III, Master Thief
- Sean P. O'Connell as Daisuke Jigen
- Mark Franklin as Ishikawa Goemon XIII
- Michele Seidman as Fujiko Mine
- Marc Matney as Inspector Koichi Zenigata
- Amanda Spivey as Murasaki
- Mike Way as Old Man Suminawa
- Paul Johnson as The Boss
- Lupin III Encyclopedia
- Lupin European Page
- The Plot of the Fuma Clan (anime) at Anime News Network's Encyclopedia
- Rupan III: Plot of the Fuma Clan at the Internet Movie Database