Gamekeeper Jeřábek's dog, the terrier Brok, takes his job guarding the gamekeeper's lodge seriously. He derives certain satisfaction when the cat Micka returns from her wanderings and cannot get inside the warm house. The cat is bored by this solitary existence and glorifies life in the big city. Brok has visited the city only once and discovered that a dog's life there is very restricted. Moreover, when he was away, a fox strangled six out of seven chickens, the tragedy culminating in the death of the cockerel who pined away from grief. Brok is very ashamed at what happened and decides to take his revenge on the fox. The gamekeeper sets out to feed the stags, roebucks and fallow deer, taking not only Brok but also the remaining chicken with him. The dog guards the chicken closely and is even concerned for the safety of the wild rabbits who are hopping about by their burrow without a care in the world. When the fox tries to catch them, Brok realizes this is his big moment. He throws himself on his opponent, taking him unawares, and finishes him off once and for all. Now Brok is contented since he has fulfilled his obligations: to guard his master's property and to protect the weak from the strong.