Chapters 1-5 introduce us to the main characters of the story, Jed and Marina. The two tell their story in alternating chapters.
In these chapters, we get background information about Jed, Marina, their families, and the Beelsonite Believers, a millennialist sect.
Marina lives with her parents, Myrna and Harmon, and her five siblings. In Marina's family, it is Myrna who becomes obsessed with Reverend Beelson's Church of the Believers. In these chapters, we also learn that the Beelsonite Believers harbor strange beliefs about the end of the world.
In particular, they believe that only 144 people will be saved after Armageddon occurs (on July 27th, 2000), as opposed to the original 144,000 stipulated in the Bible. Additionally, the sect members also believe that they must wait out Armageddon at the top of Mount Weeupcut. Marina is a little nervous about this, as her father doesn't believe in Reverend Beelson's version of the end of the world. Of her parents, only her mother is convinced of Reverend Beelson's ideas. July 27th is also the day of Marina's 14th birthday, and she isn't sure whether it will even be remembered.
Meanwhile, Jed lives with his father after his mother ran off with her lover. Jed's sister, Alice, is a sophomore in college. Like Marina, Jed feels that Reverend Beelson and his group of believers are religious extremists.
Neither Jed nor Marina are happy about how the Beelsonite religion is splintering their families. In Marina's case, conflict between her parents escalates after her mother decides to home-school the children. Meanwhile, Jed still grieves over his mother's betrayal and is having a difficult time coming to terms with his father's strange, new religion.
So, the first five chapters of the book introduce the main characters, setting, and a context for the plot.