Her Fearful Symmetry is a literary ghost novel by Audrey Niffenegger, published in 2009. The novel’s title is inspired by a poem by English poet William Blake called “The Tyger.” The novel follows the story of young identical twins, Julia and Valentina Poole. Although the girls look nearly identical, they are actually mirror versions of one another, as Valentina has her hair parted on the opposite side, and even her heart rests in the opposite side of her chest, causing her persistent medical issues.
Although they look alike, their personalities are quite the opposite, with Julia being the dominant of the two. Valentina is quiet and mousey, always giving way to her bossier sister who insists on having her way. Still, the twins do everything together, and the difference in their personalities seems to make them even more reliant on one another. Still caught up in their childish fantasies, they continue to live a codependent lifestyle that makes it difficult for either of them to develop other relationships, hence the fact that they are still both virgins. They sleep in the same bed, wear matching pajamas, and still call each other by their childhood nicknames. The twins tried out many colleges together before deciding that it wasn’t for them and moving back home with their mother.
Having grown up with their mother in Chicago, they have heard their mother talk about her own twin sister, their aunt Elspeth, but there has been a rift between the two women for many years that has gone unexplained. When their aunt dies of leukemia, she leaves the twins her flat located beside Highgate Cemetery in London. The only requirements to claim their inheritance is that the twins must live together in the apartment for a year and that their parents can never enter the premises. The twins decide to move to London to live in the flat.
When they arrive, they find that the apartment building is filled with colorful characters. Elspeth’s lover, Robert, lives in the flat below them, and upstairs is Martin, a man whose wife has just left him because of his obsessive-compulsive disorder. Robert gives tours of the cemetery, which also allows him to gather more information for the thesis he is writing about it. Robert and Valentina have an immediate affection for one another and soon begin to fall in love, as Robert sees many similarities between Valentina and her late aunt. Julia becomes friends with upstairs neighbor Martin and secretly begins giving him medication for his OCD.
Elspeth is trapped in the apartment as a ghost, although she goes unnoticed by its inhabitants. Finally, Valentina becomes aware of Elspeth’s presence, sensing her moods in the apartment. Tired of being so strongly linked to her sister, especially in her role as the weaker twin, Valentina wishes to distinguish herself and gain some independence. She asks Elspeth to remove her soul from her body so that everyone will think she has died, and she can build a new life without Julia.
Shocked by the proposed plan, Robert refuses to participate. Instead, he rifles through old letters and diaries left to him by Elspeth and, in doing so, learns what caused the rift between her and her sister. They actually switched their identities, pretending to be one another, which made it impossible for them to be in the same place at the same time.
Elspeth removes Valentina’s soul from her body, and Julia believes her sister has died from an asthma attack. She is devastated. They hold a funeral for Valentina, secretly transporting her body back to the flat where Robert witnesses her soul re-entering the body. However, he soon learns that it is Elspeth’s soul, not Valentina’s. According to Elspeth, Valentina’s soul would not re-enter the body.
Now, Valentina is the ghost haunting the apartment, and her strength is growing every day. She communicates with Julia who helps to free her spirit. Once freed from the confines of the apartment, Valentina visits the mausoleum where she sees that her coffin is lying empty.
One day, while out shopping, Julia sees a woman who looks identical to her dead sister. She notices that the woman is pregnant. The woman, who is actually Elspeth, runs back to Robert and informs him that they must leave immediately so as not to be found out. Elspeth suggests they move to Sussex as she has always wanted to live there. Robert realizes that Elspeth is manipulative and always has to get her way. This puts a strain on their relationship, but Robert agrees to move to Sussex with her. After Elspeth gives birth to a baby boy, she returns to their home to find Robert’s finished thesis sitting on the table, and she knows that he has left her.