Set as an alternative reality for World War I, two unlikely allies navigate a world of subterfuge in an attempt to bring peace. Darwinist Britain, with their fabricated animal war machines attempts to keep the Ottomans from siding with the Clanker German war machines.
Just like the first book, there is plenty of historical accuracy woven within elaborate locations and intense battle scenes. Westerfeld does not depend solely on the same cast of characters, introducing us to the Committee of Union and Progress. This rebel force provides an external plot mechanism to develop the strained relationship between Alek and Deryn.
Overall, I was pleased with this book. The pacing moved swiftly, the plot was cohesive and I feel ready to tackle the third book. The only concern I would point out to parents is that two girls kiss. Deryn continues to hide her true identity, dressing and acting like a boy, but one of the new characters (Lilit) gives her a parting kiss. I'm still not completely sure if Lilit knew for sure or not. Either way, the reader is left with an awkward situation brought on by Deryn's lack of honesty.