The Beginning
On the map Riot on Multiplayer, that map gets over raided by zombies and a guy named Gideon came to rescue a soldier. Atlas drugged 4 characters which is Oz, Dhan, Lilith, and Decker. They don't know that they are drugged, they act like and look like humans but apparently their not. They almost died but atlas saved them like i said by druging them. Thats why they were in bags with the nova sign on the bag and people with Gas Mask was there but that happens later on. It starts at Atlas and they were not warned about it. In the Cutscene the beginning Oz was talking and said "When Atlas dropped the bomb they hoped it would've finish the war. But instead it unleashed a freak show like no one has ever seen." What that means is that Atlas started all of this. They had test subjects full of zombies and they all got loose in the facility. Also When Oz said this. "No one bothered to tell the rest of us." He meant that they none of the people that were involved with the subjects didn't let anyone else know.
AW
Outbreak takes place at a place called Atlas. The 4 Main Characters use all thier Key Cards to try contacting Atlas to pick them up. Atlas tried rescuing them but the Atlas Helicopter blew up. Than they went to the next map and ended up at the map called Infection. They were in body bags with a Nova sign on it and they were knocked out and transered by Atlas. Lenox is from a Group called Sentinel. Lenox shot Oz in the head and its beacuase he's the host of the Infection, and his name stands for Original Zombie because hes patient 0. In Carrier, they switch to the Sentinel Group after Lennox, which is a new Character who shot Oz in the head which he is still alive because of the drug. The 4 Characters you now play as, is trying to blow up the ship with Oz. They saw Oz and than escape. what they don't know is that Oz made it to the next map named Descent. That is where the Characters go to and notice Oz is there. They eventually take out Oz but he returns and now he is Boss Oz. They also took out Boss Oz and at the end it shows that there are so many characters that look exactly like Oz but one of them open up thier eyes.