The boring life of Evdokim Filin, an honored orderly at the maternity hospital, flowed sluggishly and predictably until he discovered a man in swimming trunks in the lilac bushes. Having offered Owl a diamond ring, the stranger asked him to hide it until the evening. Oh, and in vain Dusya was tempted by unexpected wealth! By evening, the guy, safely hidden in the barn, threw away his skates, or rather, someone contributed to this. Our savior, as a decent person, called the police, but when the task force rushed to the scene, the man with a broken skull was no longer there. Dusya would have decided that he had imagined all this if his pocket had not been occupied by a gold ring with a real diamond. So, the benefactor is killed and his corpse is stolen. Now even the bumpkin Dusya is ready to fight for justice. He begins an investigation according to all the rules...