Andrey moved from his native countryside to Moscow a long time ago, where he continued to serve in the police. Years later, he returns home for a tragic reason: his grandfather, a fisherman, died at sea. The astute opera immediately notices the changes in the neighborhood. The residents look intimidated and secretive, and the whole city is entangled in criminal networks. Now Andrey suspects that his grandfather's death was not an accident. A new acquaintance, Vasilisa the dolphin, will help him get to the truth. According to Andrey himself, he has been able to understand these intelligent animals since they saved his life as a child.