Brundibar

– I am Pepicek, very small.
– And I am Aninku, his sister, even smaller.
– Good morning. How are you!
– And we live in a house in the yellow hills.

When Aninku and Pepicek discover one morning that their mother is sick, they rush to town for milk to make her better. Their attempt to earn money by singing is thwarted by a bullying, bellowing hurdy-gurdy grinder, Brundibar, who tyrannizes the town square and chases all other street musicians away.
Befriended by three intelligent talking animals and three hundred helpful schoolkids, brother and sister sing for the money, buy the milk, defeat the bully, and triumphantly return home.
This book is based on a czech opera of the same name («Mrundibar» is czech slang for «bumblebee»), with a libretto by Adolf Hoffmeister, set to music by Hans Krása. Completed in 1938, the opera was performed fifty-five times by the children of Terezin, the nazi concentration camp. Krása, who was jewish, was also imprisoned in Terezin. He was killed in Auschwitz in 1944.