App of the Living Dead (Gamer Squad, Bk. 3)

Bex, Charlie, and their friends have now saved their town from video game monsters and an accidental alien invasion - and they have no intention of playing the new zombie app from Veratrum Games. But everyone else in town is hooked, and when a flu sweeps the school, turning teachers and students into the undead, they discover that only non-players are immune. The Gamer Squad has to find a way to save their friends and neighbors - and stop the company from unleashing more deadly games!