It's a children story about the magic coin legend. You can get this coin in a mysterious way on Christmas Eve night. Then you can buy anything, because the coin will return to your pocket again and again.
But there's one special condition: you can spend this coin endlessly only on kind and useful purchases. If you buy something with a bad purpose, for example, for the sake of bragging or out of vanity, the coin will disappear forever and it cannot be returned.
The main character is a boy from a 19th-century noble Russian family. He passes through this legend and finds out what is right and what is wrong. He uses the magic coin to buy clothes, toys, and other things at the fair for poor people. But in the end, he feels vanity. Boy makes a try to buy a vest with pearl buttons to be in the spotlight. And for this reason, the magic coin leaves him forever.