This is the absolute shortstory, here you can read everything about the game and it's story: The four stayed focused and managed to fight through all the evil and escaped with military support into a hopefully peaceful future. They had big luck, because everyone seemed to be immune to the virus which gave them an advantage against the infected. Together with Bill, Francis and Louis they had to survive the zombie apocalypse somehow.
Now that the planet's overrun with murderous zombies, and all of her professors are dead, Zoey at least has the cold comfort that she's been studying up on the right subject after all. After spending her first semester holed up in a dorm room watching old horror movies, Zoey was given a choice: Stop fooling around and get her grades up, or drop out. Zoey is the teenage daughter of a wealthy family.