The Hearth and the Salamander : Waking up to the Emptiness of the world where no one can be offended or made to think.
The Sieve and the Sand : Montage realizes the immensity of trying to change the world, or even Mildred.
Burning Bright; The destruction of Montage's world personal and city.
The Hearth and the Salamander Montage is told how the firehouse society is built to avoid offending any minority. No one is to be allowed to be superior to anyone else. This results in an emptiness of human spirit and relationships.
The Sieve and the Sand: Montage tried to change his wife to rebuild a relationship with her, but she was too tied to her "family". He tried to wake Mildred's friends but only makes them angry and cry. His plans with the professor seem doomed to have much affect.
Burning Bright. Montage's house is burned down along with his relationship with Mildred. Beatty is burn along one hound and his career. Then the entire city is burned in an atomic war. This opens the possibility of building a new world.
The danger of political correctness and a world where no one can be offended is that it results in the emptiness seen in the novel 451