Owen is the novel’s protagonist and a 12-year-old self-described genius who experiences childhood obesity. He overcompensates his insecurity and low self-esteem by presenting as over-confident and superior, a contrast that emphasizes the theme Identity and Self-Image. He is self-aware of the physical issues and stigma consistent with childhood obesity, mentioning his physical attributes infrequently with self-effacing humor. He is also highly confident of his intelligence, which often leads to a lack of awareness of his personal biases. At times, he is dismissive of the insights of others who he presumes are less intelligent. While he is resigned and embarrassed about his body and physical appearance, he also makes mistaken assumptions and snap judgments that cause conflict.

Avoidance and repression are ways that Owen copes, which are central to the conflict and development of his character arc. Blending the Bildungsroman, a novel of identity development, with the mystery genre frames Owen’s character development and self-discovery as a process that highlights his attempts to repress trauma.

Caitlin, who goes by Jeremy, is Owen’s sister. Jeremy illustrates the novel’s theme of Identity and Self-Image as Owen views her as a socially empowered champion.