Stones are both a passion and a profession for Anna Krechetova. She has a blog dedicated to the properties of minerals. This irritates the owner of the Sapphire company, where Anna works as an expert. It becomes impossible to work at Sapphire because of the owner's nagging. Anna writes a letter of resignation. However, on the day of her resignation, a unique heart-shaped diamond disappears from the safe. The thief contacts them and sets them a condition: Anna and Fyodor go to the forest and wait for instructions. If they cope with a series of strange tasks, the thief will return the diamond.
