Note: I received an ARC from Netgalley. This story is about three teenagers. Alexis, called Allie, Rob and Juliette. They all are suffering from XP and therefore can only eave the house at night. Juliette is a former athlete and now discovered Parcour. So the three of them use the nights to practice and scout places. At one night they see a man in an apartment who tries to revive a woman. They woman already looks really pale and they believe she is dead. Allie is the only one who is wondering about this and she asks questions. Which makes her a target. Little does she know at this point that one of her best friends knows the killer quite well.The book started rather slow in my opinion I was still drawn into it because I have a thing for books which deal with medical stuff. So this was my cup of tea. At about 40% in it started to pick up the pace and the storyline got a little scarier, maybe even dark and creepy. There were a lot of twists and turns which made the book more confusing to me than to build tension. I really enjoyed the last 20% which is why I gave the book 4 stars. I'm not a fan of the ending though. A little more closure would have been nice.