Heartbreaking is right. I would also describe the story as hauntingly beautiful, heart-wrenchingly sad, yet full of hope and promise. We follow Cat from childhood to adulthood, following the twists and turns growing up in a post-disaster world and all the trials and tribulations that come with it. Throw in a set of genius parents and the fact that Cat has somewhat of a learning disorder, and you've got the right recipe for strife.And then there is Finn. At first Cat thinks he is a ghost, yet still trusts him very quickly. He is so human that she never sees him as anything other. It is a perfect mirror to our own world and the discrimination that exists.I found myself aching for Cat over and over. From the outside she has a great life, yet we are continually brought into what is really going on. She is awkward, and socially inept. She has one constant in her life, Finn, and she has to come to terms with the fact he is a machine.I was on the verge of tears throughout this whole story. It feeds you just enough hope that you keep reading, yet repeatedly takes the hope away, like pulling a rug out from under your feet.I can't recommend this enough. Even if you don't like books on social commentary, read the story for what it is; a story about how life can knock you down, but there is always something worth getting back up for.