Experiments carried out by the government caused most of the citizens to be infected with a virus that made them turn into zombies. Escaping a horde of zombies is easy for you and Diego because you are members of a government organization tasked with eradicating zombies. But it's not easy now because you are pregnant and Diego has to protect you and himself. "Don't worry. I will protect you" he has to take you back to the base but have to get past the zombies.