Inspector Ganimard III is the grandson of Lupin I's archnemesis. He has come to Japan has the head of security for the 1972 France Fair but also intends to restore his family's honor by arresting Lupin III. Ganimard publicly baits Lupin into trying to steal his grandfather's items, that fell into the museum's possession some time after Arsène Lupin's death. Ganimard is convinced that reason and science will capture Lupin.
However Lupin III manages to trick Ganimard III by hiring copies of himself to be arrested while the real Lupin stole his grandfather's personal clothes and items
This episode is the first of two times one of Inspector Ganimard's grandchildren crosses swords with Lupin III. The second is Lady Detective Melon in the second series.