I loved this book and can wait to read the next one. I thought half way through that it would be a series because... well, it too good!David and his epileptic brother get stuck in a school where a kid, carrier of a deadly virus, went to hide. The entire school becomes infected, all the adults die and only the students survive.The government puts the school in quarantine because the students carry the virus that instantly kills adults. However, as the virus leaves the body of those infected they are allowed to leave the school... if it is not too late.The school gets divided into gangs that fight for the food that is delivered to keep them alive. If the virus and fighting for food wasn't enough, David's girlfriend (Hillary) cheated on him, dumped him, and then turned into this cruel bitch and becomes the leader of her own gang: the pretty ones.Sam, Hillary's new boyfriend, has a grudge against David and is set to kill him. That, and the fact that he is the leader of the most powerful gang in the school will make David's life pretty much... a constant hide and seek.At first, David didn't want to join any gang, but due to extreme circumstances he ends up forming his own gang: the loners.Will, David's brother, is in love with Lucy who is in love with David. I liked this love triangle because the book didn't focus on it. Things happen when you are trapped in a place with a bunch of other people your age, and the romance is just one of the many things going on. Actually, it adds to the book. I mean, it was necessary for the development of the story (unlike the romance in The Forsaken).Quarantine is packed of action. There is not one minute when I got bored and felt like skipping pages. I kept looking at the bottom of my kindle to see how much was left of the book because so much action was going on that I never saw and end coming :-)At 95% percent, when usually things start slowing down, the book was actually picking up... again. The book is brutal and violent. Thomas didn't spare his characters and didn't mind to make them ugly. I hadn't read a book this good in a long time!