The premise is fairly simple: a classic futuristic walled society scenario, where those inside the wall (the Enclave) are rich and privileged, while those who live outside the walls mostly depend on help given by the Enclave. Water is a necessity and used in some ways as currency, as this is a post-climate change world where rain is rare, but water is recycled by the Enclave through the use of their more advanced technology. As if depending on the rich is not enough, the first three babies born each month are given into the adopted care of families in the Enclave, for reasons unknown - at first - in return for extra food and water. Gaia - the protagonist - is a midwife, following in the footsteps of her beloved mother, and on the eve of her first solo delivery she returns home to find her parents have been taken into custody of the Enclave and are scheduled to be executed. She then is determined to save them.
The most impressive thing about this book is that everything actually makes sense. The characters react believably to their circumstances, and the world itself is not hard to fathom. Gaia is probably my favourite heroine in a long time. Yes, she has the tendency to wonder why people would look at her with anything but disgust - she has a huge burn scar down the right side of her face - but after some time she grows to realise that maybe people can learn to look past it, and instead of whining and moaning about it she actually accepts this as a fact.
There is a bit of an "insta-romance" - but the way it's handled is a lot less sickening than other couples have been (Bella/Edward ring any bells?). Leon is a flawed character, but rather than using his darker side as a means to make girls swoon, Gaia is attracted to him for the kindnesses he shows her, not for any put-down or arrogance he may show (which is none, thank god). She doesn't take any crap from him either - when she thinks (fairly enough) that he has abandoned her, she is angry and wastes no time before putting him out of her mind and getting on with finding a way to save herself and her mother.
In fact, the most important thing in the characters' relationships is that they tend to listen to each other, and try and understand from their perspective, rather than running off in a huff or being furious for stupid reasons.
The writing style was sometimes a little annoying, and didn't always do its job but it was better than average, and I found I literally couldn't put it down. It may not be perfect, but the cliffhanger ending has me dying to read the sequel and all in all I think my faith may have been restored in the genre.