The story in Fahrenheit 451 is driven by Montag's inner conflict. After having talked with Clarisse, he begins to question his own happiness, his work, and the way he lives his life. Then he questions the way the entire society lives. He experiences an increased awareness of the social structures and limitations on his (and others') freedoms. No longer able to merely think about these things, he begins acting out. Thus, his inner conflict becomes an outer conflict. As his awakening begins to affect others (Faber, Millie, and eventually Beatty and the authorities) his personal inner/outer conflict affects the entire society. Consequently, his house must be burned, his wife leaves, he must confront Beatty, and he must finally escape.
The war that destroys the city is a secondary development but it may have to do with a conflict similar to the one between Montag and his oppressive society. Montag's conflicts and how he deals with them openly in public are what drive the story.
well the story is the character, in the theme. So basically the setting is the characters in the conflict.
Hope that answered your question.
Cheers, John Rhys Martin