Aninku and Pepicek find their mother sick one morning. The doctor says they need to buy her milk to make her better, but they have no money. They try to make some by singing in the town square, but a hurdy-gurdy grinder, Brundibar, chases them away. With the help of three talking animals and three hundred schoolchildren, they defeat the bully. Brundibar is based on a Czech opera for children that was performed fifty-five times by the children of Terezin, a Nazi concentration camp in 1943.