Aza, a 16-year-old high school student, is eating lunch in the school cafeteria with Daisy, her best friend since elementary school, and Mychal, an artistic friend. According to present-day Aza, the first-person narrator, this day was when she first began to think of the possibility that she was not truly “real,” that she was like a character in a fictional piece.

Aza thinks incessantly about such matters, as she suffers from obsessive-compulsive disorder and severe anxiety. For many years, she has compulsively pressed her thumbnail into the pad of her middle finger, so a callus has grown there. She obsessively worries about bacteria entering her body, so she feels compelled to regularly reopen the split in the callus, drain the wound, clean it out, and put a fresh Band-Aid on her finger. Aza is particularly obsessed with contracting the bacterial infection Clostridium difficile, C. diff, and constantly monitors herself for symptoms. She feels helpless to resist the compulsion.

Sitting in the cafeteria, Aza pulls out her phone to read about the human microbiota, another compulsion. Because she has been focused on her “thought spiral,” Aza has not paid attention to her friends, who are discussing a local billionaire named Russell Pickett.