Just as humanity was about to start colonizing other worlds, an asteroid struck Earth. The survivors call it Wormwood, the star prophesied to fall upon the Earth as a harbinger of the apocalypse. It was sent by God as a punishment for the sins of mankind, especially the mass abandonment of religion in favor of science.
Jude is a priest in the new Theocracy. But when his brother, whom he thought dead, turns out to be alive but scheduled to be executed, Jude's faith is tested.