From the publisher's website:
Everything has changed. No more paperwork or errands or ballgames. We still fight and squabble and lie as much as ever, but not for money or drugs or power. When the world has been overrun by the living dead, survival is the only thing that matters. Banding together always seems like a good idea in theory; strength in numbers, right? Keep believing that if you want, but those people just might kill you before the zombies. Remember, only one thing matters: staying alive.
To be clear, this supplement is an add-on, designed to be used with another playset. Zombies in a nice southern town? Perfect. Zombies in the Old West? Of course! Zombies on the grassy knoll? Oswald is the least of Kennedy’s problems.