Apocalypse, Book 1

First came the comet. Then came the sickness. And then They came. A comet hurtles towards the earth. There are only days before impact. Something must be done. Days later, some people begin to stagger and stumble along out on the streets. Something is wrong with them. At first they are only isolated cases; then larger and larger numbers of people are affected. What is it? A mysterious disease. No one knows what it is or how it's transmitted. But it's an epidemic. And then it gets worse. Then They show up. This is now Book 1. (Originally Books 1 and 2.) From the author of I Am Legion, Skyfallen, and The Doom Bearers.