Greta Stuart has been a hostage for most of her life. Well, technically, she's one of the "children of peace". You see, long ago, after the world was ravaged by the effects of global warming, an AI named Talis put himself in control, and decided to almost completely eradicate war by having the leader of each country turn over their heir to be a "child of peace" until the child reached the age of 18. Should that country go to war, the child will be killed. Greta's nation, the Pan Pols (Canada) are about to go to war over water, and Greta knows that her death is imminent.
This book is hard to explain. Basically, the world-building is pretty detailed, but not without some holes (many of which are explained by the end of the book), and most of the first half of the book was spent explaining the world that Greta and her fellow hostages lived in. Also, Greta is the proverbial ice princess - she is fairly stoic, even in her own head, and so I didn't think she was very likable for the first half of the book.
However, as the book progresses, Greta really comes into her own. Her stoicism and propriety have given her a certain amount of power in regards to the fellow children of peace, and it's really fun to see her step up and wield that power. And then, stuff goes terribly, horribly wrong, and the pacing and intrigue of the story really pick up.
I'd give the first half of the book 2 stars, and the second half 5. So, over all, like a 3.5 or something. By the end, I was loving it. If you like really complex dystopian novels (this is more like 1984 than Divergent), then this one is not to be missed.