The main character of the series "Dolphin" is police officer Andrey Korablev, who believes he can communicate with dolphins. When Andrey's grandfather dies at sea, he returns from Moscow to his hometown, Yuzhnomorsk. He wants not only to bury his grandfather, but also to find out who is responsible for his death. He meets Inna from the Oceanography Institute and her dolphin, Vasilisa. His new aquatic friend "tells" Andrey that the former gangster Borovikov is buying up land on the coast. But Grandpa didn't want to sell the plot.