[2][3][4] The film tells the story of two boys, Misha and Dima, who are preparing for the birthday of a pioneer organization.

While fishing, Misha falls into the river, but is saved by a stray dog, Savva, who after that was taken by a furrier.

Misha and Dima tried to save Savva, by any means, risking jail.

They secretly swam to the illegal shelter of the keeper, who is revealed to be a dangerous criminal.

Finally, when the school engages in discussion about whether Mishka and Dima should be suspended, a police officer came to school with congratulations for discovering and helping to liquidate a dangerous criminal.