While escorting Gerry Lane back to his plane, Captain Speke and his team are attacked by zombies. Speke is infected and kills himself to prevent becoming a zombie.
After concocting a theory that the zombies only attack healthy humans, Gerry Lane and W.H.O. employees fight their way through the W.H.O. facility to reach terminal but curable pathogens. Cut off from the rest of the group, Gerry infects himself after reaching the pathogens. It works as a camouflage and Gerry makes his way back to the group.
The camouflage idea is spread to the rest of the world and is used to fight the zombies, but Gerry still believes that it will only aid in the progress of the war and not end it.