Zom-B Baby by Darren Shan

B has spent the last few months bunking with the Angels, a group of teens dedicated to eradicating the evil dead from the face of the earth, beginning with the undead roaming the abandoned wreckage that was once London. But the Angels' mission is a bit more complicated than that, and B takes to the streets of a very changed London to decide: is it a mission really to be believed? But instead of answers, B finds a horror beyond imagining.