Unraveling the Dark Secrets of Mary Kubica’s “The Other Mrs.”

Sadie Foust

is the novel’s protagonist and primary narrator. She is introduced as an introverted and troubled woman, dealing with her husband’s affair and her son’s behavioral problems. She is the main breadwinner and a modern woman who is determined to protect her family. However, Sadie is also a vulnerable character who struggles with serious memory lapses and periods of lost time, which lead to bizarre and even violent behavior. She is unreliable, often blaming others for her actions and taking herself and the reader down false paths. The mystery of the novel is ultimately her own identity, as it is revealed that she has dissociative identity disorder (DID). In the end, Sadie survives her husband’s violent betrayal, brings her family to safety, and begins to heal.

Will Foust

is Sadie’s seemingly perfect husband. He is handsome, charismatic, and well-liked, and Sadie views him as the “voice of reason” in their marriage. However, this persona is a facade. The reader learns that Will is a manipulative and violent antagonist. He murdered his fiancée, Erin, years ago, and used his charm and manipulation to convince Sadie’s alternate personality, Camille, to murder Morgan and another woman who threatened to expose his past. He gaslights Sadie throughout their marriage, even switching her medication with placebos to maintain control. When Sadie gets too close to the truth, Will’s true, monstrous nature is revealed, and he attempts to kill her.

Camille

is one of Sadie’s alternate personalities. She is a manipulative and sexually aggressive character who is the physical opposite of Sadie. She sees herself as a foil to Sadie, mocking her appearance and lack of confidence. Her possessiveness and jealousy of Will lead her to commit murder at his manipulation. Camille is more self-aware than Sadie and appears when Sadie is feeling threatened, giving Sadie a sense of control over a situation. However, her actions—including committing multiple murders—are a result of her own violent tendencies and a past trauma.

Mouse

is the third of Sadie’s personalities, presented as an innocent and empathetic six-year-old girl. She narrates her sections in the third person. Her personality was likely formed in childhood as a way to cope with severe abuse from her stepmother. Unlike the other narrators, Mouse’s memories are pure and kind, reflecting her simple, loving world before the abuse. Her story is a heartbreaking “once upon a time” that was never fully realized.

Imogen

is Sadie’s niece who comes to live with them after her mother’s suicide. She is a troubled teenager who looks and acts like a goth, but she is actually a deeply scarred young woman. It is revealed that she helped her mother die, at her mother’s request, a burden that explains her aggressive and antisocial behavior. Imogen’s character serves as a red herring, as Sadie suspects her of a crime, but ultimately, she becomes a deus ex machina, saving Sadie’s life by hitting Will over the head, reinforcing the novel’s theme of female resilience.

Otto Foust

is Sadie’s introverted and troubled 14-year-old son. His problems are rooted in his mother’s dissociative identity disorder. He was tormented at his old school, and it is revealed that it was Camille, not Sadie, who encouraged him to seek revenge. Sadie’s suspicion that Otto is involved in the murder is a red herring, as his behavior is a direct result of his mother’s undiagnosed and untreated mental illness.

Tate Foust

is the youngest of the Foust children, a cheerful and carefree 10-year-old who provides a stark contrast to his troubled mother and older brother. He is confused by his mother’s erratic behavior, especially her denial of shared memories and games. His simple love for his mother and his frustration with her inconsistent behavior highlight the profound impact of Sadie’s mental illness on her family.

Officer Berg

is the police officer investigating the murder of Morgan Baines. He serves as a source of information for both Sadie and the reader, revealing clues and background details that counter Sadie’s biased perspective. His role is to build suspense and act as a red herring, as Sadie becomes convinced he is a corrupt officer. His unprofessional conduct in the investigation is also subject to critique, as he allows Sadie to go home unescorted after learning of her DID.

Morgan Baines

is the neighbor whose murder is the inciting incident of the novel. A beautiful and seemingly vivacious woman, she is a source of jealousy for Sadie and rage for Camille. It is revealed that she is the younger sister of Will’s long-dead fiancée, Erin. Morgan realized that her sister’s death was murder, not a suicide, and she was murdered by Camille, who was manipulated by Will to keep his secret safe. Morgan’s death drives Sadie’s investigation and the novel’s plot.

Jeffrey Baines

is Morgan’s husband and a red herring. Sadie immediately suspects him of his wife’s murder, even though he was out of town. Her suspicion is based on pure speculation and is later revealed to be completely unfounded.

Girl Baines (unnamed)

The unnamed six-year-old daughter of Jeffrey and his ex-wife, Courtney, discovers Morgan’s body. She is a key plot point and serves as a red herring for the reader. She is similar to Mouse in age and circumstance, leading the reader to believe that they might be the same person. However, it is revealed that they are separate characters.