Plague World — Dana Fredsti

The thrilling conclusion of the zombie apocalypse begun in PLAGUE TOWN and continued in PLAGUE NATION! The zombie plague has gone airborne, and the conspiracy that began it all reaches the boiling point.
 
Having been ambushed in San Francisco, which is now fully engulfed in the zombie plague, Ashley and the wild cards must pursue the enemy to San Diego. There they will discover a splinter of their own organization, the Dolofónoi tou Zontanoús Nekroús, which seeks to weaponize the plague. But that isn't the worst news. The plague has gone airborne, making it transferable without physical contract. It cannot be controlled by anyone, so reports of the zombie swarm are coming in from across the United States - and across the world.