Thomas Neville must decide whether to choose for the Angels, or the Demons in this, the final volume of The Crucible.
This being a book by Sara Douglass, however, things are never quite as they seem!
As in the other two books in the series, the setting is an 'alternate' history - people who are knowledgeable about the time period may be confused by seemingly 'incorrect' facts, but these are deliberate, to provide a suitable setting for a fictional story.
If you enjoyed the rest of Ms Douglass's books, I recommend this one, but read the rest of 'The Crucible' first!