Plague Nation — Dana Fredsti

Having stopped the wave of the undead that swarmed their facility, Ashley Parker and the other wild cards (those immune to the zombie virus) are assaulted by an unknown enemy and forced to travel to a secret laboratory in San Francisco.

En route some are killed, while others are kidnapped by their shadowy foe, who seems to use the zombies as a weapon. But the worst is yet to come, as the plague begins to manifest in key locations nationwide. And the truth begins to emerge about the paramilitary society, the Dolofónoi tou Zontanoús Nekroús (DZN).