Inspector Lestrade brings to Holmes a situation regarding a man who hates Napoleon Bonaparte so much, he shatters plaster busts of him. One was smashed at Morse Hudson’s shop, the origin of the busts. Two more were sold by Hudson to Dr. Barnicot, one of his home, the other for his branch office. Both were smashed following a burglary wherein nothing else was taken. The bust was taken outside the house before it was smashed. To Holmes, the common element is obvious: they come from the same mold. The culprit is more than just a Napoleon hater.
An urgent telegram the next morning alerts Holmes and Watson to another bust-breaking, this time with a murder. The dead man is found on his doorstep, throat slashed. A photograph of a man with simian features is found in the dead man’s pocket. The bust, from the same mold, was taken by a burglar, and fragments of it are found in the front garden of an empty house up the street. Holmes sees there is a streetlamp there, so clearly the perpetrator wanted to see what he was doing. Anything closer would have been too dark to see.
Holmes learns who sold the busts and to whom they were sold and where they were made. The informants also recognize the man in the photo as an Italian immigrant named Beppo, who worked in the shop where the first bust was broken until he left two days ago. Inquiring further, Holmes discovers the busts are part of a batch of six. Beppo is recognized as a rascal who was in prison for a street brawl stabbing the previous year but has since been released.
Lestrade reveals that the dead man is Pietro Venucci, a member of the mafia. His conclusion is that Venucci was there to kill Beppo but wound up dead himself.
Holmes sends an express message then invites Watson and Lestrade to join him. He’s expecting another bust-breaking at a house in Chiswick. Lestrade thinks it secondary to the murder, but comes along anyway. Beppo shows up, enters the house, and exits a few minutes later with a bust. Upon shattering it, he examines the pieces, allowing Holmes and Lestrade to attack and arrest him.
Holmes buys the remaining bust, making the owner sign over all rights to it. Then he smashes the bust, revealing the black pearl of the Borgias. The owner’s maid is the dead man’s sister, Lucretia Venucci. Beppo got the pearl from Pietro and hid the pearl in the bust at the shop where he worked just before his arrest. Learning who bought the busts, he proceeded on his search to reclaim the pearl.
This particular story is all too similar, in my mind’s eye, to “The Adventure of the Blue Carbuncle.” Sadly, that’s what kills it too. The earlier story is far superior.