Do you oil your war machines, or do you feed them?
It's 1914, right at the beginning of World War I. In these novels by Scott Westerfeld, however, the Central Powers have developed huge mechanized war ships, whereas the Allies use genetically modified creatures (first developed by Darwin, of course). Alek, the would-be-heir to the Austrio-Hungerian throne is on the run for his life. Deryn is a Scottish girl who disguises herself as a boy so she can enter the British air force. Thrown together unexpectedly, can these two unlikely friends keep the world from ripping apart at the seams?