The book opens in a bleak place… a morgue, to be exact. Cullen Witter's arrived along with his mother and younger brother Gabriel, to identify the body of his dead cousin Oslo. If you think that things are bad for the Witters right now, just wait—they get way worse. During the course of the next couple of weeks, Cullen tries to finish out his last year of high school in the small town of Lily, Arkansas, without feeling too depressed and weighted down by death.
He even goes on a double date with his best friend Lucas, who brings along a girl named Alma who has just moved back to Lily after a failed marriage. When he comes back from his date though, his brother Gabriel is missing. Cullen, his parents, his aunt Julia, and Lucas all wait for Gabriel to return… but he doesn't.
Ultimately, the summer turns into a miserable time, during which Cullen spends all his time searching for his brother. At the same time, the town of Lily is mesmerized by a dude who shows up proclaiming that he's seen a supposedly extinct woodpecker in the town.
Everyone is excited by this new development, hoping that it may put their small town on the map, but Cullen is resentful because he thinks that people should care a lot more about Gabriel's disappearance than the emergence of some stupid bird. He ends up breaking it off with Alma as well, and ends up going out with the girl he's been pining after for years—Ada Taylor.
At the same time, the book weaves in the seemingly unrelated tale of Benton Sage, an eighteen-year-old missionary who goes to Africa in order to save souls. He ends up coming back because he's not suited for that missionary life, and his strict family is so disappointed in him that they stop speaking to him or acknowledging his existence. Talk about melodramatic, right?
Benton goes off to college, where he meets his new roommate, Cabot Searcy, a rich playboy. They somehow end up getting along pretty well, although their friendship is cut short when Benton throws himself off the church bell tower on Christmas Eve. After that, Cabot goes kind of crazy trying to find the meaning in life. He starts taking on Benton's religious fanaticism and becomes convinced that it's his mission in life to do God's work.
Later on, we find out that Cabot ends up marrying Alma, so that's the story's connection to Cullen Witter. She regrets the hasty marriage pretty quickly (after all, he's kind of a kook), and divorces him to move back home to Lily. Cabot follows her and becomes furious when he finds out that she's dating some kind named Cullen, so he goes over to the Witter household in order to kidnap Cullen and show him who is boss… and ends up taking the wrong brother.
Instead of admitting his mistake, Cabot becomes convinced that Gabriel is the actual Angel Gabriel and decides that this is all a part of God's plan, so he takes the poor younger Witter boy hostage for weeks on end. Yikes.
At the end of the book, all these converging storylines come to a head. Ada breaks up with Cullen because he doesn't really love her; he just loves the idea of her. It is discovered that the extinct bird never really did come back—the whole thing was a publicity stunt engineered by a desperate, attention-seeking man. And Gabriel returns to his family, making everything whole and good again.