The Jew’s Breastplate by Arthur Conan Doyle. Short summary

5 seconds

A thief steals precious stones from a museum. But because of his love for the daughter of the old curator, Dr. Andreas, he returns them to the old man. The doctor tries to stealthily return them to the museum.

1 minute

Young scholar Ward Mortimer becomes curator of the Museum of the Ancient East. His predecessor, Dr. Andreas, has left his post unexpectedly.

Before he left, he showed the museum’s main treasure, an ancient gold thimble from Judea, richly decorated with rare gems.

After a while, Mortimer discovers that the stones in the thimble have been tampered with. He thinks it is a fake, but the stones turn out to be genuine.
Mortimer and his friend hide in the museum and catch the intruder. It turns out to be Professor Andreas. He explains the reasons for his strange action.

Andreas’ daughter fell in love with the thief, who had taken the precious stones from the museum and replaced them with fakes. Because of his love for the girl, he decided to give up his trade and gave the professor the stolen jewels. The professor had to return them several nights in a row.