Ninety years from now, a satellite detects a nearby black hole scientists dub Kali for the Hindu goddess of destruction. Humanity embarks on a generations-long project to tap the energy of the black hole, and found colonies on planets across the solar system. Earth and Mars and the moons Europa (Jupiter) and Titan (Uranus) develop radically different societies, with only Kali, that swirling vortex of destruction and creation, and the hated but crucial Artificial Accretion Disk Development association (AADD) in common.