Storyline:
After the first attacks, you are sent to the city to protect the people that live there. Soon you’ll discover that you’ve taken on a bit more than you were planning on, but thanks to a brave escape on top of a skyscraper you find an abandoned bank that seems safe. Thanks to a team of clever scientists you discover the source of the problem. You will need to go to  atop secret military base in the middle of the desert to learn more. After the first attacks, you are sent to the city to protect the people that live there. 

After surviving a huge attack at the military base, you discover that everything started at this base! The scientists collect samples and they create an antidote. Now you just need to stroll through a nearby town on the way home. How hard could that be?