Two interwoven stories about a mysterious scientific facility called Haven, and two girls whose paths cross because of it. You do need to read the stories in a specific order starting with Lyra's story.
Lyra's only memories are of Haven. She is one of many replicas(otherwise known as clones), and one of the oldest. She interacts with nurses, doctors and other replicas, but doesn't know anything about the world outside Haven. An attack on the facility causes her to join forces with a male replica to try to survive. This is where she bumps into Gemma.
Gemma's story is quite different. Gemma grew up in an affluent house, but has very few friends. Her parents are extremely overprotective. When she finally convinces them to let her go on a road trip with her best and only friend, they relent. Then the attack on Haven happens and they change their minds. Gemma starts listening in on her parent's conversations and for the first time in her life becomes suspicious of her life. When Haven's name keeps coming up she takes off in pursuit of answers.
The story moves very quickly. There are a few twists and turns that will surprise you, and some that probably won't. The characters are interesting and overall like-able. I did feel like Gemma's characters focused a little too much on the "I'm overweight so I'm not pretty" idea and I didn't like that at all. It's a mashup of sci-fi, adventure and romance. I think some of the ideas around cloning and the ethical issues surrounding it are interesting, but not heavy handed. Overall, a good book.
Appropriate for 11 and up