Lauren Oliver seems to be a hit or miss author for me. I really enjoyed the Delirium series but haven't really been a fan of any of her other books, much like Panic and Vanishing Girls, Replica was just okay.
Lyra doesn't have a past except for living in Haven. She knows she's a replica but what she doesn't know is just how dangerous that is, until she meets the boy trying to escape. Gemma lives on the outside, she knows of a secret location known as Haven but doesn't really know what they do. But then the truth comes out and her life will never be the same.
Replica is a really cool idea of flipping the book over to read another story with another character. But I think it actually hurt the plot more than anything. The world-building felt really weak and I think that's because we read some of the plot twice with these two characters -- switching POV'S throughout the book would have been better, the story could have been a bit longer and we would have learned more.
I thinks some will really like this, but for me it focused too much on the romance and we didn't learn enough about Haven or what these replica's were actually being used for.