Based on a Czech opera performed 55 times by children in Terezin, a Nazi concentration camp, Brundibar is a story of two enterprising children trying to defeat an adult bully.  They are desperately trying to get their hands on some milk for their sick mother. They sing for coins in the town square, but unfortunately, all the money in town seems to be going to the nefarious hurdy-gurdy man, Brundibar.  They join voices with 300 other children and earn enough coins to fill their milk buckets.  With subtle references to the Holocaust within tiny details of Sendak's chaotic, jam-packed illustrations, the story can be appreciated by adults who comprehend it's statement against tyranny, and by children who will see it as a simple children's story about cooperating to overcome adversity.