London is overrun by zombies over the age of 16 whose main food source is healthy children. The zombie disease happens when people are above ground which is never explained, although one of the adults seems to have an inkling of the cause. However, he dies. People die willy-nilly in this book. Death should bring some emotional response to the reader, but I was never vested in any character so I didn't care who was killed off. Kid survivors have sought refuge in deserted London buildings where they can fortify and protect themselves to some extent against the killer zombie groups. Arran is the leader of one of those groups with his second, Maxie, who has a crush on him. They only know of one other group, the Morrisons, holed up like them.
After they rescue a lone boy under zombie attack at their door, he explains there are groups like their own all over London, Maxie and Arran are surprised. The boy is the only one left of his scouting group trying to get kids to join forces at Buckingham Palace. After a scavenging hunt gone wrong, food becoming scarce, and adults attacking their compound more often, Arran and Maxie along with the rest of their group are more than ready to leave, except Callum. His fear has made him have symptoms that resemble agoraphobia. He refuses to leave and stays behind. The adventure to the Palace is full of perils with not everyone makes it alive. At the Palace, the groups learn about oppressive leadership and must decide their futures.
Maxie is the protagonist and the voice of reason in an insane world. She keeps her humanity and is willing to speak up. While she is supposed to look strong, the reader doesn't see how others look at her. The result is it looks like she is being manipulated by the boy leaders and is only interested in having a romantic relationship. She is described as being not pretty and a great fighter, but she isn't really intriguing. The characters were very one-dimensional for me.
Survivor Sam is the alternate point-of-view and he just spends his time on the run and staying alive. He gains confidence with each dire situation he manages to get out of, but I got bored with the repetitive pattern after awhile. I also thought some of the chapters wasted because when there is a chance to explain what had happened to the adults, it is not given. Another point-of-view is Callum. Why bother? He's supposed to show the psychological trauma of trying to survive a zombie apocalypse but he is more like a deer in headlights. And again, Callum is not rounded out in way that the reader can understand.
Kids love scary books and this one will make 'em shiver, but its execution misses the mark. While the violence isn't graphic, it is gross. The zombies explode, ooze pus, live in filth, and are decayed. I was disgusted because I actually dreamed of zombies last night and woke up with my heart racing. I've never done well with the horror genre. Can't do the movies or the books. If you do read it, go in with low expectations and don't plan on having your questions answered as this haphazard plot sets up for the sequel.