Contamination

For three thousand years, an alien oversight body has watched Earth from a station hidden in the darkness between star systems. The work was never meant to be complicated. Catalog the species, measure their development, predict their trajectory, file the reports every fifty years like clockwork. Humanity was difficult to assess but not impossible. Violent, chaotic, repeatedly on the verge of destroying themselves, but survivable as a subject of study.
Routine, in the way that difficult things become routine when you have been doing them long enough. Then the reports stopped. When investigator Rievenor arrives in New Orleans with thirty days to retrieve three observers who have gone silent since 1987, he expects to find negligence. What he finds instead is something the institution has never encountered in three thousand years of watching civilizations rise and collapse into the cold maturity of species that have made their peace with a universe that does not care about them.
One observer has been living inside human bodies for two centuries and cannot locate the boundary between his cover and himself. One has watched a single family across twelve generations and stopped filing reports the night she watched them laugh at a funeral. One plays jazz on Wednesday nights and has not filed anything since Ronald Reagan was president. None of them want to leave. None of them can explain why humans, alone among every species ever cataloged, did this to them.
The determination panel is convening. A decision is coming that will determine whether eight billion people are welcomed, quarantined, or quietly erased. Rievenor has thirty days and a species that should not be able to do what it does. On day six, he goes to hear the jazz musician play. He does not file his day seven report.