This is a book I read in a couple of days, and then spent a couple of months thinking about. Then I read it again.
It starts off, as many SF stories do, with humanity exploring the galaxy, colonising planets, and then coming into contact with an implacable alien force bent on humanity’s destruction.
Humanity is reduced to a few colonists sent off in a desperate last-ditch effort to re-establish the species, and stay low-tech and out of sight until humanity is ready to face the aliens and win. Instead, the colony directors brainwash the colonists into believing them to be angels, sent by god to rule over them. The military directors argue against this, there is a fight, and the ‘angels’ manage to wipe themselves out.
Nine Hundred years later, a robotic body is activated, complete with the memories of a young ship’s officer. Her task, given via recorded message, is to go out into a society ruled over by a rigid church that has banned technology, and prepare the way for the second coming of humanity.
Her name is Nimue Alban and hers is one hell of a story.