Holy crap this book blew my mind. I was pulled into this book from the very beginning. It was so weird and so cool at the same time. One of my all time favorite young adult sci-fi books. There was so much suspense throughout I read this in one sitting. Lancaster kept me guessing as to what had happened to everyone, and when you finally find out that humans were getting a software upgrade, and that this had happened before I thought it was awesome. I had no clue that was the answer to what was going on. One of the my favorite twists in any book I've read. It's not revealed but I hope Kyle and his girlfriend choose to stay like they are. Awesome book.