It's a great book, worth reading.
The action is in Warsaw, Poland on a brink of the second world war. It shows a pre-war situation, in elegant & and a beautiful Zoo in Warsaw. It's well organised with many exotic animals (elephants, camels, tigers, hippos, etc).
The zookeepers were trying the way of looking after the animals during the war.
Also, they risked their life to save their Jewish friends, hiding them in the cellars under their home.
Lots of 'risky adventures' during German occupation. Saving Jews was punished by death.