This, as the front of the book proclaims, is a zombie sequel and second in the trilogy of David Wellington's books. While the first book, Monster City, focused on the mission of a handful of people to the undead infested regions of New York, this book travels back in time to the start of the epidemic and explains why it happened. The focus is split between two characters, a not so ordinary civilian who calls herself Nilla and an army man given the task of clearing up the mess. The story is engaging and the research for the zombies is interesting. I would like to know how this fitted in with the second book as regards time line, as it seems to contradict some occurrances in Monster City, but better understanding of the time line might sort that out. As can be expected from all zombie books, especially the second novel in a trilogy, it doesn't end happily but I found it hard to put down. Well done for Wellington in keeping up the momentum. I give it 7/10.