THE ENEMY WITHIN San Francisco has been overrun, and the zombie plague has gone airborne, spreading across the globe at an incredible pace. Wherever people travel, the virus is there, leaving swaths of bloody devastation. Within weeks of becoming a wild card—immune to the deadly virus, possessing enhanced speed, strength, and senses—Ashley Parker faces trials she never could have imagined. For the zombie plague was planned, by unknown enemies who hide in the shadows. They've infiltrated the ranks of the wild cards, and kidnapped the one person who might develop a cure. They've also taken Gabriel, the man who holds Ashley's heart. Now she and her team must locate and take the enemy's stronghold... before the world passes the point of no return.