Thursday is the first-person narrator and protagonist of the novel. She is a young woman who lives in Seattle and works night shifts as a nurse. Thursday believes she is married to Seth Ellington as part of a plural marriage, and she spends most of the novel obsessing about the women she believes are his other two wives. In reality, Thursday is Seth’s mistress, but when she miscarries his baby, she has a psychotic break and weaves a reality in which they are married.

Thursday is an unreliable narrator, a trope often used in psychological thrillers to heighten suspense and involve the reader in solving the plot’s puzzle. Thursday’s obsessive behavior means that once she gets hold of an idea, she cannot let it go. This aspect of Thursday’s personality allows Fisher to plant clues that are easily overlooked because Thursday is pulling the narrative focus in a different direction. Thursday’s first stay in the psych ward reveals that her version of events has been misleading, especially as it concerns Seth’s relationships with Regina and Hannah. Lauren’s report that she cannot find the things that Thursday asks her to look up solidifies the extent of Thursday’s illness, which turns into rage when she is forced to confront reality.