Turtles All the Way Down

by John Green

Aza Holmes is a 16-year-old high school student living in Indianapolis who struggles with OCD, which often manifests as a fear of the human microbiome. Constantly worried about infection, particularly by C. diff, she repeatedly opens a never-fully-healed callus on her finger in an effort to drain out what she believes are pathogens. Throughout the book, Aza is accompanied by two close friends: Mychal Turner, an aspiring artist, and her best friend Daisy Ramirez, who writes Star Wars fan fiction.

One day at school Daisy discovers that Russell Pickett, a billionaire construction magnate and the father of one of Aza's old friends, Davis Pickett, has gone missing in the wake of fraud investigations. Tempted by the reward of $100,000 for information leading to Pickett's arrest, Daisy takes Aza on a search for the missing billionaire. After canoeing across the White River and sneaking onto the Pickett property, they are caught by the security guard who brings them to meet Davis.

To persuade the two girls to stop pursuing the elder Pickett, Davis gives Aza $100,000 taken from his father's various stashes around the guest house, which she splits with Daisy. After the meeting, Davis and Aza begin dating and, at the same time, Daisy becomes romantically involved with Mychal. As time passes, Aza comes to believe that she cannot overcome her anxiety, preventing her from ever having a normal relationship with Davis. She finds numerous blog posts written by him about his feelings on both his father's disappearance and his relationship with her.

Aza reads Daisy's fan fiction for the first time and discovers that Daisy has been using it as a vent for her frustrations with Aza. She continues to spiral into a panick attack which results in her drinking a bottle of hand sanitizer, and passing out. Their friendship briefly deteriorates, culminating in a heated argument while Aza is driving that results in a car accident. Aza spends several weeks in the hospital. She recovers and rekindles her friendship with Daisy once she is healed.

At an underground art exhibition inside an unfinished drainage tunnel system off of Pogue's Run (that Pickett's company was responsible for), Aza and Daisy go exploring on their own, where they finally solve the mystery and realize that Pickett had run to the very place they were. After noticing a putrefaction emanating from the area, they suspect that the billionaire had already died. Aza tells Davis of their discovery, and the latter eventually places an anonymous tip to the police on where to find the body.

Given the loss of their parents and home (their mother died years prior), added to the fact that their father had left his entire fortune to his pet tuatara, Davis and his younger brother Noah decide to relocate to Colorado, where they have rented a house and would be attending schools. As Davis and Aza say their goodbyes, she reflects on the open possibilities of her future.