The movie is set during the last days of a foreign intervention against Soviet Russia. Police are searching everywhere for a Bolshevik named Brodsky but cannot find him. Meanwhile, a man named Michel Voronov serves as a teacher to a rich woman's son, Zhen'ka.

On one of his trips through the nature reserve, the ranger Michailytsch found a young lynx whose mother was killed by a bear. He takes it with him to his log cabin and calls it Kunak, which means friend. The young lynx gets used to the human environment. He grows up to become a stately lynx. When he attacks a rooster one day, he is sent away. On his wanderings through the Siberian forest, he is caught in a poacher’s trap. Only after a long search does Michailytsch find Kunak and frees him. But the lynx came to the attention of thieves who catch it and sell it to a circus in the city…

The action takes place in 1920 during the Civil War. Crimea on the eve of complete liberation from the White Guards. Returning from patrol, the four brave “elusive” knocked down an airplane. In the field bag of the captured pilot, they find a secret report, which speaks of the existence of defensive fortifications around the coastal city, which the Reds have yet to take. Young heroes get the task to get a map of fortifications and go to the city...