Bubble Cities
Control-freaks are tricking humans into killing not zombies, not walkers, but simply sick people who may or may not have diseases, viruses, etc. They're persuading people to live inside the Smart Bubble Cities, the Matrix, in Toronto, Austin, Denver, London, etc. In the end, they'll try to nerve-gas everyone (in the Bubble Cities) to cleanse the planet of the homo sapiens for once and for all. Are you going to just let them do this?