Anna Khvostova - a bright eccentric middle-aged woman - lives with her beloved son Kostyk. She works as a realtor, and in her spare time she enjoys reading detective stories. Anna is bursting with pride when she learns that Kostyk has been given a position in the police investigation department. She is sure that her son has a great future in the fight against crime! However, very soon Anna notices that the senior investigator of the department - Major Golub - is biased towards Kostyk. He is constantly ironic about the young man's abilities, lets go of his hairpins and overestimates his work. To prove to Golub that his treatment of Lieutenant Khvostov was unfair, Anna begins to help her son investigate the crimes. The active participation of the mother provokes an angry protest from the young man, but this does not stop Anna. She finds herself in the thick of things again and again.