What is the main conflict in The Fifth Sacred Thing by Starhawk?

The Fifth Sacred Thing by Starhawk is a post-apocalyptic novel set in 2048 in California. While the rest of the state is dystopian, living in fear and in poverty under the military and religious control of the Stewards and Millennialists, the main characters of the novel live in the City (what was once San Francisco), an egalitarian community in harmony with the Four Sacred Things that sustain life - earth, air, fire, and water. The novel's perspective shifts between three characters from the same household, the Black Dragon House: Maya, Madrone, and Bird.