Eva was created for a single purpose: she's a backup copy, an "echo" of another girl. If Eva's "other" dies, she will step in, seamlessly replacing the girl and living out the rest of her life in her other, Amarra's, shoes. Her whole life is spent learning to be just like her other: eating the same foods, doing the same lessons, watching the same movies, learning all about the other's family and friends, etc. The rules she lives by are rigid--she can't so much as read a book her other hasn't read, and she can't leave the tiny English town where she's hidden for fear of hunters, assassins whose sole purpose is to find and kill echoes. Even the name she gave herself is taboo and must be kept secret from the Weavers who made her and dictate her life. But she's lucky enough to have Guardians who love her and will occasionally break some small rules so Eva can have a life of her own.Then Amarra dies, and Eva is thrust into a world where she must learn to get along with a family she's known only in pictures and videos, a family who knows she's not Amarra but look for glimpses of their lost loved one in every move she makes. She spends her every waking minute pretending to be someone she's not, living in fear that someone at school will out her as an echo or that her other's family will decide to send her back with a "sleep order." If she's found out, it will mean her death, if not at the hands of hunters then by the very Weavers who created her. Weavers don't have a use for echoes who fail.This whole book is about grief. Grief and selfhood and the bonds of family and friendship. I cried more than once while reading it. But at the same time, the plot has enough sci-fi thriller elements that the overall tone of the book is exciting rather than depressing. I loved it. I loved it so, so much.I loved Eva, even if I thought she was stupidly reckless sometimes. (At least there were characters in the book who pointed out that she was being stupidly reckless.) Her internal conflicts are probably some of the best I've seen in YA. I thought nearly all the secondary characters were done well too. I loved Eva's Guardian-family, and I loved Amarra's family, and I loved the love interests and the way their own conflicts, which were different and yet related to Eva's conflicts, were given attention too. There are some characters I would have liked to know better, but the cast was fairly large for a single book, so I suppose there just wasn't room for us to learn all about every secondary character.I was also really pleased with the setting. Bangalore! Awesome! Especially awesome is that the setting wasn't presented as ~exotic~. Eva did not marvel at how incredibly non-English it was, though she did do things like goggle at cows in the middle of roads and slip up by referring to chips as "crisps" and so forth. Otherwise, we were just kind of plopped into India like it was no big deal. This is how it should be. So much love.I'm really upset that this book has been out for almost a year and there's been no sequel announcement. The author wrote on her website that she planned this to be the first of a series, and I am dying for more. But it seems like this book didn't sell well enough for the publishers to go in for more books. SO ANGRY. THIS BOOK IS SO GOOD. YOU SHOULD READ IT AND BUY COPIES SO THE PUBLISHER WILL CHANGE THEIR MIND ABOUT SEQUELS.In short: My favorite read of the first half of 2013.