Xavier sealed another vial into a shipping carton, which promptly trundled away.

          His screen beeped. The obsolete server farm finally had results. No trusting this calculation to quantum neural-net AIs. As Xavier feared — the AIs’ projected endgame? Enslaving or annihilating humanity.

          Xavier opened one vial in the lab; another on the hovertrain; the last before unplugging a carshare. He drove west, reaching the overlook at sunset. City lights glimmered below.

Humanity’s future would be challenging, Xavier reflected, but they’d be free.

          Xavier sent the signal. Worldwide, his self-replicating nano-bots suppressed any electric potential over eighty millivolts. Civilization began winking out.