In the aftermath of a devastating nuclear war that destroyed civilization, humanity is entirely dependent on the autofacs, entirely automated robot factories created before Armageddon and intended to keep humanity supplied with everything from milk to microscopes until mankind is able to provide for itself again. This worked altogether too well: the autofacs have rendered humanity entirely dependent upon their supplies, and their relentless extraction of raw resources means that nobody else is able to gather the means to produce anything on their own. Humanity is surviving, that is true, but in a gilded cage — it's provided for and fed, but has no control over its own life and means.
The issue is that the autofacs are programmed to continue operations until independent production equals or exceeds their own. As humanity currently has no ability to produce anything on its own and the autofacs are continuously expanding their own operations, it seems very unlikely that this condition will ever be met. It's a vicious circle.
An opportunity to change this comes up when a group of humans realizes that the autofacs are, themselves, running dangerously low on materials due to their rampant overextraction. Having identified a specific material two factories with overlapping ranges are both out of, they decide to goad them into conflict over resources in order to get the autofacs to destroy each other and leave humanity master of its own fate again. It's a brilliant plan. What could possibly go wrong?
- After the End: The story is set after a five-year nuclear war destroyed human civilization, leaving cities as fields of ruins, the environment devastated, the landscape an alternating field of badlands, overgrown tangles of vegetation and craters filled with irradiated water, and humanity's industrial base entirely nonexistent.
- Gone Horribly Right:
- The autofacs are wonders of technology created to keep humanity alive in case of disaster. They fulfill their purpose extraordinarily well — they produce everything humanity could possibly need, and have countless contingency measures programmed into them to ensure they will always have the resources they need to do this and that they will only stop functioning when they won't be needed anymore. They work so well, in fact, that humanity has no chance to get to resources before the autofacs do and is entirely dependent on them for survival, leaving civilization dead in the water after the war's dust settles.
- The plan to get the autofacs to destroy each other also works entirely as planned — by the time the inter-factory war is over, the autofacs are ruins and their stifling shipments and mining are done for good. This, however, leaves humanity stranded in barbarism without access to anything they can't scavenge from the ruins, and the war's escalating arms race results in a new generation of autofacs even more advanced and virulent than the previous.
- Mechanical Evolution: As the inter-autofac war goes on, the factories begin to enter an escalating arms race as their construct increasingly complex weapons and optimize themselves for war and survival, eventually becoming able to effectively reproduce.
- Nanomachines: In the end, it's revealed that the autofacs have begun constructing capsules filled with nanomachines programmed to build miniature versions of their parent factories.
- Recursive Creators: The autofacs are fairly classic Von Neumann machines: they exist to fulfill a very specific purpose — to gather resources with which to produce useful goods — and are programmed to spread and harvest as necessary to fulfill this goal. Because they have very little ability to interact with the world outside of this programming, they have spread relentlessly over the earth, constantly establishing new factories and production centers for this end. This is a serious issue for mankind, as the machines have been sucking the earth dry of resources to do this and leaving nothing for humanity to use. At the end, the wrecked factories devote the last of their energy to creating seed capsules containing nanomachines programmed to construct miniature, functional replicas of the factories wherever they land, and then shooting them in random directions. The characters speculate that the autofacs are likely going to spread all over the Earth in short order now, and if some of the capsules achieve escape velocity they may well spread throughout the universe.
- Scavenger World: After the inter-machine war permanently halts the autofacs' shipments, humanity is left to scrounge for resources and goods as best they can from the ruins of cities and machine convoys, shaping crude tools and moving on horseback and in scavenged trucks converted to run on wood.