Ninety years from now, a satellite detects a nearby black hole scientists dub Kali for the Hindu goddess of destruction. As human society expands to Mars and beyond, the generations-long project to harness the power of the black hole pits the retrograde humans of Earth against the imminently rational men and women of the Artificial Accretion Disk Development association. While conflicts simmer, a mystery within Kali itself tests the limits of intelligence--both that of human and machine.