The Infection.

(4?) Groups of Apocalypse survivors trek through the wasteland that is our broken world. Ever since the first infection of the virus, everyone that has been bit by the flesh-hungry cannibal race, becomes a victim of the incurable disease... That is, if they aren't completely devoured.
James and his two sisters search for anyone else that could make their journey less lonely.
Laura and twin sister Lynn search for anyone able to provide help to their injured friend.
Others search for anyone who may know of a cure. While one group unknowingly holds it within their reach.
They must hurry, because the disease is mutating, changing on an ongoing basis. The change is becoming faster, and the mutated zombies are becoming stronger. It's going to take everything everyone has to survive.