Sherlock Holmes is often visited by Inspector Leistred. One day he talks about a strange incident: someone stubbornly smashes the statues of Napoleon. Hearing that this was a burglary, the great detective decides to investigate.
A few days ago, in a shop selling paintings and statues, the clerk left the store for a moment and heard a crack. When he returned, he saw that the plaster bust of Napoleon, worth only a few shillings, had been smashed. Because of such a trifle, the investigation did not start. Not far from the bench lives a famous physician, a passionate admirer of Napoleon. His house is full of books, paintings and relics associated with the French emperor. Recently he bought two busts in the shop. One set at home, and the other in his office. At night, his house was robbed, but the robber carried away only the statue of Napoleon and smashed it. Arriving in his office, the doctor found that the second statue was smashed to smithereens. All these busts are cast in the same form, therefore, they hunt for these statues.
The next day Leistred calls Holmes: there was a murder. One journalist bought a bust of Napoleon in the store. At night, he heard a noise, and then a terrible scream. Going downstairs, the journalist saw the man’s body near the outer door. In the pocket of the murdered was a photograph of a journalist, and next to it – a bust of Napoleon, broken into small pieces.
The great detective is studying the situation. A penny bust cost a person’s life. All the busts of the criminal broke near the light source, which meant that he had to see the fragments.
Holmes goes to the shop and shows the clerk a picture. The bailiff is familiar with this man –... the Italian artisan Beppo, who does small works in his shop. He is a good worker, but he disappeared a few days ago. Holmes finds out the address of the workshop where the busts are made.
The master informs the great detective that six busts were made. It also seems strange to him that someone destroys a product that costs a penny. Busts are cast as follows: from the two halves of the face mold cast, glued together, and then dried in the corridor. Beppo master knows well, he worked in his workshop, he was a good worker. A year ago, Beppo wounded an Italian with a knife and was arrested. It happened right after the busts were sold. Holmes determines who sold two more busts.
In the meantime, Leistred establishes the identity of the murdered: it’s Italian Pietro Venucci, one of the most terrible thugs in London. Holmes and the police are ambushed in the house, where the penultimate of the busts is. The offender takes out a statue from the house, and the police grab him. It turns out to be Beppo, who stubbornly does not want to talk, why he breaks the busts.
The last remaining bust Holmes buys from its owner. In the presence of Watson and Leistred, the great detective breaks the statue and carefully examines each piece. In one of them he finds the famous black pearl of Borgia, which was stolen from Princess Colonna. Attempts to find the pearl were unsuccessful. Suspicion fell on the maid Princess Lucretia Venucci, the sister of the murdered Pietro, and a few days later Beppo was arrested.
Beppo stole a pearl from the family of Venucci and hid it in one of Napoleon’s busts. Coming out of confinement, he established who sold the busts, and tried to find the jewel.