I ended up checking this book out from the library because I was able to get an egalley of the 2nd in the series, and so of course needed to read this first. I'd been interested in the series for a long time, the premise sounded really good.
Now I'm not sure if this is supposed to be a futuristic world where something has happened to cause people to be born with 2 souls, or if it is kind of an alternate world where that is just how things are. I do know that it is after a war, where people fought those who kept both souls, or hybrids as they call them, and it is America. In this world, by the age of 4 or 5, the dominant souls usually begins to take over and the recessive soul goes away. But sometimes, as in Addie and Eva's case, the recessive soul is still hanging around in the background. But they have to be careful, and no one can know because they would take them away and "fix" them. And Addie and Eva don't want to make any trouble for their family because their younger brother Lucas is sick, and they don't want to do anything that would keep their family from getting what they need to help him. But one day one of the weirder girls at school, Hally, seems to start being around them all the time. And one day she gets them to come home with her, and the tea she gives them, well, it knocks them out. Or more specifically it knocks Addie out, and lets Eva come to the surface. After it wears off, Hally and her brother Devon invite them to come over to learn more about how to help Eva come out and be able to sometimes control their body. They know about this because they too are hybrids. Hally and Lissa, and Devon and Ryan. The drug was easy to get because their mother is a nurse. But they should have been more careful, because Hally and Devon are also considered a foreign race, and that makes them more dangerous to those trying to "cure" the hybrids. And one day Hally does something, runs off by herself, and is caught. When she's caught, then they come after Devon. And soon they show up at Addie and Eva's house. They tell her parents they just want to do some tests, and they'll only be gone for a few days. But once the girls get to the place/compound, 2 days gets extended. And they find out from talking to their father that their brother was able to get on a list for a surgery for something to help him. All because they let the girls go, and let them keep them. Turns out this place may not be actually curing the kids. And some kids may not be making it past the actual surgery to help them supposedly. While all 3 of them, or you might say 6, are there, soon they must make a plan to get out before one of them is put under the knife.
A very interesting story. I'll be interested to see where it is going next. And maybe there will be more to answer my original question, and maybe it's not needed.