Knox is an elementary school student and the middle child of three siblings. One of the characteristics that he must manage in the novel is his ADHD. When the novel opens, Knox does not know that he has ADHD, and he frequently becomes discouraged for his proclivity for getting into trouble and acting impulsively. This has unforeseen consequences, such as the time he jumps a fence to get his soccer ball at school, requiring his mother to skip an interview to get him. He is shocked when he learns that he has ADHD, but with the assistance of Christopher and his father, Knox comes to accept his neurodiversity. After all, ADHD is what helps him hyper-focus on things he enjoys, and he learns that his ADHD does not need to hold him back.

Knox and his brother, Bowen, have a difficult relationship throughout much of the novel, though Knox craves a closer relationship with Bowen. When they get along, Knox gets excited and hopes that things will stay good between them. When Bowen treats him cruelly, Knox’s feelings become very hurt. For example, when Knox believes that he and Bowen are starting to get along better, Bowen angrily confronts Knox about the headphones he hid.