In the beginning of the book, Brent is just like any normal teenager who struggles to find his place among his high school peers. He is perhaps a little self-conscious, but he knows that he has to appear confident and sophisticated if he wants to impress. At a party, he desperately tries to talk to a girl he's had his eye on for a while. However, his efforts fall flat when the girl, Brianna, rebuffs him in front of everyone, and he becomes the laughing stock of the party.
Greatly humiliated, Brent, with alcohol coursing through his blood, takes to the wheel and decides to put an end to his miserable life. However, he doesn't die; instead, he ends up killing Lea Zamora, an eighteen-year-old high school student. When Brent discovers who he has just killed, he is overwhelmed with guilt and grief. Lea was, by all indications, a model student. She was a member of the orchestra, a member of the student council, and an athlete on the track team at Niles North High School. Lea was also an honor student, a volunteer at the Resurrection Hospital, and an active member of the Filipino community.
Seemingly overnight, Brent's life changes irrevocably. He's no longer interested in impressing anyone, and he becomes a loner. Shell-shocked and depressed, he eats little and converses little. The import of what he's done is shattering, and Brent struggles to live with himself. In light of Lea's death, he finds it difficult to discuss his attempted suicide with anyone. He is profoundly horrified that he never once considered the possibility that his actions could have resulted in someone else's death.
At this point, we begin to realize that the catastrophe Brent has just experienced is a life-changing event. As the story progresses, he begins a journey of self-discovery and redemption that both inspires and encourages him to continue Lea's legacy of goodness and joy. Brent embarks on his mission when Lea Zamora's mother gives him the seemingly impossible task of building four whirligigs and depositing them at the four corners of the United States. Although his parents initially balk at the bold request, Brent decides that he will do everything he can to honor Lea's memory.
Thus, in selflessly given himself to the tasks at hand, Brent finds new peace, confidence, and courage, all the things he's never had before. After he finishes his last whirligig in Maine, Brent is finally able to unburden his feelings to a sympathetic artist, who supports his project. What she tells him completely changes his perspective about forgiveness and redemption. The artist assures Brent that he's still a good person, despite his terrible mistakes. For his part, Brent is touched that, even after revealing his part in Lea's death to her, her perspective about him doesn't change.
By the end of the story, Brent comes to understand that Lea's memory will always be a part of him. When she died, she also managed to touch his life in a way that neither of them could have envisioned. Brent realizes that he has become the chosen conduit for Lea's joyful legacy; this realization so heartens him that he becomes hopeful that he will have the confidence to face his parents, Lea's mother, and a new group of peers in the fall. Unlike the 'old' Brent, the 'new' Brent is hopeful and enthusiastic about his future.