The novel opens with a Prologue that features Jack’s apology letter to an as-yet unknown recipient in which he confesses that he has prosopagnosia. He explains that prosopagnosia is a disorder that prevents sufferers from recognizing most people’s faces. Jack explains that his prosopagnosia is not “an excuse” for a “shitty thing” he is about to do, though he is not clear about what that terrible act is (15-16). He ends the letter by telling the recipient that he or she is the only other person who knows about his condition.

From there,Niven moves into the first section of her novel, titled “Eighteen Hours Earlier.” True to the title, the narration returns eighteen hours earlier to Libby Strout, a 16-year-old, morbidly-obese teenager. She provides her history as “America’s Fattest Teen,” telling the story of how she had to be rescued from her home by a crane after suffering a panic attack. The short version of the story, as Libby calls it, is that her mother died and she became overweight in her grief, weighing in at 653 pounds at her heaviest. Libby insists that her father is not to blame for her weight gain. She explains that she has since lost 302 pounds, leaving her about 190 pounds overweight, but that she is “fine with that” (22).