At the collective farm’s animal-breeding station, the young naturalists lose a fox named Serebryanka, which has run away. The children ask an old hunter, Mukhtar-aga, to catch the fox with the help of a golden eagle. The hunter agrees. In the duel with the fox, however, the eagle is defeated. Mukhtar-aga is distressed: the bird is no longer fit for hunting. Then the children decide to catch a young eaglet and give it to Mukhtar-aga. Khasen and Sasha set off for the mountains…