Sixth-grade student Raina Telgemeier visits Dr. Dragoni’s orthodontist office in San Francisco with her mother and younger siblings, Amara and Will. After giving an awkward smile for a medical photo and meeting with the doctor, Raina learns that she needs braces to fix an overbite, with Amara teasing, “You’re gonna be a METAL-MOUTH!!” (2). Raina is upset until she receives some advice during her Girl Scout troop meeting, which includes Melissa, Emily, Karin, Nicole, Jenny, Kaylah, and Kelli. Jenny, who already wears braces, tells her that they are not so bad if she avoids a long list of foods.

That night, Raina goes home with Kelli and Melissa. Melissa eggs the others to race her to Raina’s house, but Raina trips and falls on her face after trying to grab Kelli. Raina soon realizes that she is missing her two front teeth. One falls on the ground, and the other wedges into the top of her mouth. Raina’s father cares for her while her mother calls another dentist, Dr. Golden, to perform emergency surgery to put the teeth back in and place a plaster seal.

Raina runs through a range of emotions. At first, she finds the missing teeth funny—“I look like I’m six again!” (12)—but her amusement fades as her codeine medicine and diet of broth and ice cream make her feel queasy.