It's been only two weeks after the total collapse of society. Robots were the new thing, employed by companies everywhere, and were not too complex, no safety or security flaws were reported, until a simple analytical error caused police robots and guard bots too to register everyone as their target. The robots are far too simple to become sentient or become evil, but the ones tasked with defending and apprehending criminals have had an error within their criminal database, making them hostile.