It is the cusp of World War I, and all the European Powers are arming up. The Austro-Hungarians and Germans (Clankers) use Kerosene-driven iron machines loaded with guns and ammunition. The British (Darwinists) employ fabricated animals as their weaponry. Their Leviathan is a whale airship, part of the British fleet. Aleksandar is the son of duke Franz Ferdenand who is on the run from the Darwinists who use fabricated animals as their war machines. His parents were killed and with the help of two of his father's assistants he hides from the enemy until he can take his father's place as ruler of the Clankers. The Clankers use machines for war instead of animals and they think its wrong to use animals. So naturally, the two groups are at war. Meanwhile Deryn is abord the Leviathan training to be a pilot, but instead of planes they use animals to fly. One of the best books for your child to read this summer! This is a new and original concept that is easy to pick up, but impossible to put down!!!