As the most frequent narrator, Stephanie is the protagonist of the novel. Although the conclusion of the novel increasingly focuses on Emily, the narrator and the reader spend the most time with Stephanie in both her interior chapters and her blog posts. She lives with her five-year-old son, Miles, in Connecticut following the death of her husband, Davis, in a car accident. Because of Davis’s life insurance, Stephanie doesn’t need to work, but she starts a blog focused on motherhood in order to connect with other mothers and to banish her feelings of isolation. In addition, Stephanie’s blog allows her space to consider the Societal Expectations of Mothers, a theme that recurs throughout the novel. Through her blog she champions mothers helping one another and sticking together; however, over time, this benign mission becomes twisted when she becomes complicit in helping Emily cover up murder and in falsely accusing Sean of abuse.

Although Stephanie appears to be just another “Captain Mom,” as Emily and Sean call them, her personal history is much darker, and her story exemplifies the theme of Living a Double Life. On one hand, she is a successful “mommy blogger,” who offers tips and camaraderie for other moms who follow her blog.