The TV series "Police Brotherhood" is a detective action film about two generations of investigators from the St. Petersburg Criminal Investigation Department. Elderly police officer Shavyrin learns that he is terminally ill and decides to end his life on his own terms. Meanwhile, Colonel Tarasov, who was once convicted for a professional crime, is released from prison. He wants to seek revenge on the gangster who caused him to serve time. However, during this time, Shavyrin's daughter Nastya meets Tarasov's son Nikita. By chance, the children change their parents' plans.