The Sacrifice picks up after Small Sam and The Kid arrive at the Tower of London at the end of The Dead. Though Sam finds safety and friendship at theTower with Jordan Hordern's crew, he can’t settle down. The only thing he wants is to be reunited with his sister, Ella. Ed is reluctant to let Sam go after her, because it would mean traveling westward through the forbidden zone. Ed begs Sam to wait until DogNut returns with news of what’s going on in the center of London. Eventually, though, Sam and the Kid can’t wait any longer, and they strike out on their own. It turns out that the biggest danger they face is not from sickos, but from another group of kids. Meanwhile, Shadowman is tracking Saint George across north London, watching him build up his army. Shadowman knows that Saint George is an extremely dangerous threat, but no one will take his warnings seriously. Some answers to the questions we've been wondering about--What is the Disease? Where did it come from? Is there a cure?--are addressed by an unexpected source: a diseased adult nicknamed Wormwood who has the ability to speak, though his ravings are difficult to decipher. It will take a few more books for all of the truth to come out, and for all of the loose ends to be tied up in an apocalyptic battle between the army of the sickos and the combined forces of the various kids around London.