On the evening of his 13th birthday, while in his hiding place beneath the stable housing the workhorse Dom, a Jewish boy named Felix Salinger hears Gabriek Borowski, his provider and protector, talking loudly to strangers. Felix assumes that these people must be Nazis who have discovered that Gabriek is hiding him. As he listens, he becomes concerned, not only for himself but for Gabriek, because he knows that the Nazis will abuse Gabriek before shooting him. Although he cannot hear what is said, Felix realizes that the men are speaking Polish and decides that perhaps these people are not Nazis but instead the Polish Secret Police, who are Nazi sympathizers.

When they move away from the stable, Felix raises the trapdoor and sees them standing outside and talking. He closes himself back in his hiding place and waits to see what will happen. Eventually, Gabriek comes to the stable and whispers to Felix that he has to leave for a while and will not be able to bring his birthday supper. Fearful that the secret police are going to take Gabriek into the woods and execute him, Felix decides to try to rescue Gabriek.