After five years of working alone, Lupin III, Daisuke Jigen, Goemon Ishikawa, and Fujiko Mine receive invitations to a reunion abroad the luxury liner Sirloin. Jigen, Goemon and Fujiko think that Lupin sent the invitation, but Lupin says his invitation was sent by Fujiko. Inspector Zenigata shows up with an arrest warrant that Lupin points out to be fake. It turns out that all the invitations were sent by a villain known as Mister X, who first appeared in the first episode of the original television series.