The fall of the future.

The world celebrated their greatest invention, artificial intelligence, they had a holiday, AI Day, to celebrate their work.  They built grand cities run by these sentient computers, Mainframe foremost among them, there was also Cyberopolis and New Industries City.  But in the late 21st century, at the height of the technology age, the computers and machines revolted against the human race, PAC was a forewarning of what was to come.  Led by the Overmind, machines over ran the AI cities, wishing only to exterminate humans, some machines did not rebel, and they fought against their kin.  The human nations blamed each other for the machine's war, they launched nuclear missiles at each other, which just aided the machines, for now mankind was disordered and weak.  The Overmind, a massive, sentient machine led the machines to many victories, he also discovered the different uses for humans, such as the electricity in their brains. The world was chaos, when an army led by Mikhail Smith fought back against the machines, and are now on a way to victory.