It only takes one moment for what you consider normal to change
When your classified military program gets decommissioned before you can fulfill your purpose, you can't help but feel the last few years of your life have been a total waste of your stolen youth. You might also notice that you're really bad at assimilating back into "normal" civilian life. Side note: Assassin training doesn't come with a lesson on social skills.
So when inhuman figures with a revolting stench crash through the windows, attack everyone, and knock you unconscious before you can bite into your pizza, you find upon waking that normal loses its meaning.
My name is H. Booker and everyone around me is either missing, dead, or worse. What's worse than death? That would be these creatures. Rotting but somehow agile, zombie doesn't even begin to describe them. Now my family is missing and my city of Washington D.C. is under quarantine with no way in or out. I need to find answers and save those left behind in this madness before the government resorts to radical solutions to wipe out the problem, and the city along with it. My knack for weapons, cars, and finding a few strays along the way may come in handy after all but time is ticking and I need to save myself and what's left of humanity before it's too late.