The story is narrated by ten-year old Staszek, who writes in his diary about his school-friend Jozef. Jozef comes from a family of blacksmiths, all of whom bear the name Jozef. Since he is the sixth consecutive son to be called Jozef, he is nicknamed Szustek (meaning "sixth one").
Adaś Miauczyński, a Polish intellectual, has severe alcohol problems which affect his relationship with his son Sylwek.
