In the After, all children are born as twins, always one female and one male, with one of them deformed. The perfectly healthy child gets dubbed an Alpha, while the other is branded an Omega, to be segregated, reviled, and the scapegoat for all that is wrong with the world. Only one thing saves them from execution, a life link to their twin; what one suffers, so does the other, including death. Most Omega's have a physical difference, whether it is a missing limb or a mutation, Cass is one of the few who doesn't, she is a seer. By staying with her brother Zach longer than most, she may have brought about unfortunate consequences, for Zach's paranoia and anger forges him into a driven man. The Reformer would see all Omega's under complete supervision and he has an Omega seer called the Confessor to help him. The story is told mostly from the point of view of Omega's, and yet we never see the Alpha's as the bad guys, just misguided. In a world that splits itself into "us" and "them", Cass is the only one that sees they are all the same. She understands that Omega's can't keep hiding, and Alpha's can't keep on living in fear. How do you change the mindset of people though, when both sides point their finger at each other, especially when this attitude stems from sibling quarrels? This question plagues Cass. Haig is one of those authors that just has a way with words, although she can be a bit repetitive. She is poetically descriptive at times, yet at others, she is so subtle that all we have is a feeling that something more is going on. Some of these suspicions are left for other volumes to answer. In either case, The Fire Sermon has a spellbinding effect on us. The circumstances may be complex, but at its heart it is as simple as the relationship between a sister and brother.