Egor felt like the most unhappy person in the world. How did this stupid fifty-ruble note get into his shirt pocket? After all, he knows for sure that he did not take other people’s money! But the contents of mom’s wallet have decreased exactly enough, and now everyone in the house considers him a thief. Well, Yegor has someone to ask for help! Ilya, a loyal friend and a real detective who has already solved several crimes, promises to look into the situation. And first of all, he proposes to take under supervision... the nanny of little Petka, Yegor’s brother. This respectable lady is behaving very suspiciously...