ok, added a few key characters.  Want this to be character driven, so you can mention a sickness, however no zombs just yet.  Maybe Jagon, you're swat character can take down a drug dealing house with his fellow swat boys.  I'll have Johnny be one, and then Dallen can become his lawyer.  We'll eventually get all the characters together, then bam!  zombies lol.  

By the way, I am working on making this a comic book as well.  So keep that in mind.

As for the zombies, there will be zombs just like in the walking dead, but there will also be special infected.  I'll post more on that later.  As for how they come to be, there's a virus going around.  Sort of a major flu, but it doesn't turn you into a zombie it just kills you if you get it to bad.  There will be a giant meteor shower occur across the united states  (think Armeggeddon bad), which will have something within the rocks of the meteors.  This alien substance will mix with this flu virus and create the zombies.  

Our characters won't know any of this for a very long time, if ever.  Depends how the story goes.  But, first we build characters, then the meteor shower that affects the world, then zombies.