This is like the store-brand version of [b:The Golden Compass|119322|The Golden Compass (His Dark Materials, #1)|Philip Pullman|https://d.gr-assets.com/books/1436741101s/119322.jpg|1536771]. It's still pretty good, and better than nothing, but it's also kinda doing it a favour to compare them.

Premise: What if Archduke Ferdinand was murdered after 200 years of steampunk? What if he had a kid who survived him?

I liked the giant walking machines, and the giant biological constructs, but I never quite believed in them. I loved Deryn, who is crossdressing so she can serve in the air-corps, and although I believed in her, I had trouble believing in Alek, who seemed at times so naive I was guessing he was twelve when I was told he was fifteen.

I had the most trouble believing in Deryn's sudden sexual awareness of Alek, who is honestly a bit of a wet rag. She's a fifteen year-old girl who's serving on a ship full of men, and you're telling me Alek gets her motor running? Have you met fifteen year old boys? I detect and resent the invisible hand of the author, here.