While demonstrating the flaws of a museum's security system to prove a point, Holmes inadvertently allows master criminal Giles Conover (Miles Mander) to steal the pearl.
Pursued by police, Conover hides the pearl inside one of six wet plaster busts of Napoleon in a pottery shop.
The story centers on the theft of the "Borgia Pearl," a valuable gem with a sinister reputation for bringing death to its owners.
