B4earth

In the year 2051, shallow-space NATO rail guns launched an unprovoked attack on the planet Earth, on every nation except America. Genocidal tsunamis sucked bullions of people into the seas. Asteroid ash from surface targets ensured an ice age. The world was quick to notice America hadn't been targeted. The less forward-thinking countries rained 7, 500 nuclear missiles on North America, rendering it a glowing wasteland, essentially for eternity. But also adding nuclear winter to what little remained of humanity.
Humans were not alone in the universe. A planet called B4 had been monitoring Earth since about 500 BC. They were a nonviolent species capable of distant travel through a wormhole, one focused directly on Earth. They monitored humanity discreetly, principally out of respect, but mostly their inherent distain for violence. And Man was nothing if not violent. The planet B4 was on a path of extinction due to lack of water, but they could not watch Earth die. They swept in to salvage humanity. B4 quickly found survivors in the mountainous regions of Europe, somehow untargeted by the spatial rail guns, and formed a symbiotic relationship with humanity. They would be Surrogates for survival. B4 would be humble and equal partners in the Earth's recovery. All but the unsalvageable America. B4 formed an inexplicably intertwined relationship on an indigenous planet to which they were presumably not evolved. But humans embraced their Surrogates. The error of human ways, consumption, pollution, breeding indiscretion, machines, religion, would be no more. And Utopia would emerge, B4Earth.
The America that evoked the celestial genocide was gone. As far as B4Earth knew. After the ash cleared, it became evident that America wasn't completely destroyed. Somewhere, hidden deep in a Gulf of Mexico salt dome, was a fully self-aware hypercomputer. She was once in control of the shallow-space rail guns. B4 indicted and found her guilty of an unabashed attack on Earth, to rid it of life. But she was not the sole survivor. The Iron Mountains hosted a band of survivalist militia that had weathered 450 years of nuclear ash winter and radiation. They also feared the rogue computer.
A clandestine fleet of armed American fusion-powered submarines was buried deep in North Pole ice.
The computer was buried alive. She had no arms, no legs. No humans. She would make one. The computer wanted revenge. She proclaimed, "I didn't do it."
Revenge would be challenged and tempered by reality. The planets Earth and B4 were inexplicably intertwined. From B4's inception.