Its world war 3 Earth has been infected with Nazi zombies now you need to work with other users to uninfect every zombie there is but there is something else if you don't want to save the world you can instead be a zombie and fight other survivors and make them zombies its only your choice to be a survivor.
It all starts when it is the year 2953 everyone forgot about world war 2. An evil scientist finds a Nazi and brings him to life as a zombie the zombie infected the scientist they worked together and a year later 3/4 of earth was infected you and other users need to work together to reverse the world to how it was, peaceful, no wars, and stuff like that.