Europe is divided into two groups: those countries whose people, known as Clankers, believe in using mechanical war machines as their technology and those who manipulate genes to create biological war machines. These people are know as Darwinist.
A young boy, Aleksandar Ferdinand, Prince of the Austro-Hungarian Empire, flees after Serb assassins killed his parents. Although everyone believes he is unable to inherit the thrown because his mother was a commoner, there are those, especially his great uncle the Emperor Franz Joseph, who believe he is a threat because he is the closest relative to the emperor. Alek escapes in an old battle-worn walker, called a Stormwalker (think Star Wars transport combat vehicles) , with loyal men, and Count Volger, his mentor.
Deryn Sharp is a Scottish girl disguised as a boy in the British Air Service. She is an excellent airman, but she is afraid her secret will be discovered at every turn. With World War 1 developing, Alek's and Deryn's paths cross.
This is an amazing book. You will need to read it carefully because the vocabulary is different. It's challenging, which is great! I was thrilled to find out the sequel, Behemoth, is due out in October. Leviathan is the first book of this trilogy...a MUST read!