Imagine a society very much like ancient Egypt, but clearly not on our Earth as their planet (strictly a moon) orbits a gas giant. Now imagine that this society has learned how to harness the power of Jung's "collective unconscious", collecting the power of dreams and even a person's entire "life force" to cure disease and injury.
This is Gujaareh. The Goddess Hananja's Gatherers go out into the night and gather the Dreamblood and Dreambile of those judged corrupt by the Hetawa - Gujaareh's religious power. In the process, the "corrupt" are sent permanently to the land of dreams. Sharers collect the dream stuff from the Gatherers, and on a lesser scale directly from the dreams of others, and use it to cure the sick of the city.
Obviously, such a system is open to its own corruption. A person's enemies might bribe the Hetawa to find him corrupt. If you have access to a large amount of Dreamblood, it can be used as an addictive narcotic to control others.
Ehiru is the greatest of the Gatherers. When he finds that the practice of Gathering, which he has always believed exists to root out and destroy corruption is corrupt itself, what is he to do? Does he tear it down and throw out the baby with the bathwater?
The Prince wants to be free of the addiction of Dreamblood that caused his father to dance to the Hetawa's tune. Should he eliminate everyone and everything to do with it, at any price - even his own corruption?
Who is good, and who is bad? Which is the greater Evil...
I love a good fantasy, and especially a good fantasy in a foreign setting (in her afterword, Jemisin comments that far too much fantasy is "Simplistic British Isles Fantasy Full of Lots of Guys with Swords And Not Much Else", which is itself rather simplistic, but certainly strikes a chord with me - not that I mind a good Arthurian legend...). I particularly like stories outside of the normal, and this story drew me in quickly and deeply. I'm looking forward to volume 2.