Kate Mara, star of “The Undermothers”, on Nancy’s traumatic past, her secret affair with [SPOILER], and her final months

Spoiler warning: This article contains details from episode five of “The Undermothers,” now streaming on Apple TV

According to the CinemaDrame news agency, there is a great deal to unpack about the character Nancy Hennessey, played by Kate Mara, in “The Undermothers.”

The Pasadena socialite — whose murder opens Apple TV’s mystery thriller — is a difficult figure to fully understand. Raised in a Bakersfield trailer park, Nancy has a complicated and painful past that viewers only glimpse before she ultimately marries Robert (Joel Kinnaman), a wealthy and influential man. In the first three episodes of “The Undermothers,” told from the perspective of her best friend Eleanor (Kerry Washington), we learn that Nancy has been secretly involved with a mysterious man named David.

While police and Nancy’s friends believe her lover may be responsible for her death, David’s identity appears to be revealed in episode four, when a bartender of the same name begins interacting with Nancy at a New Year’s Eve party at the Pasadena estate. However, when she rejects his advances, the story circles back again — until, in the episode’s final moments, Nancy jokingly refers to Howard (Corey Stoll), the husband of Mary (Elizabeth Moss), as “David.”

In episode four, Nancy experiences a series of emotional blows: tense interactions with her husband, her father-in-law, and even her daughter, who publicly slaps her at a party. Deeply humiliated, she leaves and is followed by Mary and Eleanor. She is forced to confront traumatic childhood memories, including repeated abuse from her mother’s boyfriend and her mother’s own neglect. She also attempts to apologize to her daughter Cora (Adria Arjona), but is rejected. Meanwhile, she believes she has discovered divorce papers on Robert’s laptop.

In episode five, Nancy begins working on the ballet production “Ariadne” at Metro Ballet Los Angeles, where she helps the unemployed Howard find a job. Over time, their daily collaboration develops into friendship and eventually, after a drunken night at a wrap party, into a secret affair. Nancy later learns the truth behind Robert’s distance: he has lost much of his fortune in a bad deal and believes separation would protect her financially. Relieved rather than devastated, Nancy tells him she loves him regardless of money. They reunite for opening night of “Ariadne,” where she ends things with Howard despite his objections. However, Robert later discovers Nancy’s affair after Howard anonymously sends compromising photos. Enraged, he becomes violent, and in the final scene, Nancy is seen fleeing in a car.

In an interview with Variety, Mara discusses Nancy’s traumatic past, her relationship with Robert, and why she entered the secret affair.

On portraying Nancy across flashbacks rather than the present timeline, she said she didn’t treat her as someone separate just because she is not in the present timeline, explaining that she plays her as a living person in a different period. She added that the series itself moves across timelines for all characters, not just Nancy.

On Nancy’s vulnerability and pressure during a looming divorce, she said Nancy lives under constant anxiety and pressure, with a strained relationship with her daughter and husband, and is trying to build a career without emotional support, which shapes her decisions.

On ballet as both trauma trigger and passion, she said returning to ballet after more than twenty years is both terrifying and exciting for Nancy, because it reconnects her with something she once loved, but also forces her to confront unresolved emotions from her past.

On her language when discussing childhood trauma, she explained that all of Nancy’s experiences shape her decisions, relationships, and emotional dynamics in adulthood, just as they would in real life.

On reading the source material, she said she read the book because the scripts were not fully available yet and that it helped her understand the character’s trajectory.

On the Howard twist, she said she thought it was a great surprise and that moments like this keep both the show and book engaging.

On Nancy’s denial in the affair with Howard, she said Nancy likely does not want to believe what is happening and is in denial, making choices she could have avoided but does not.

On why she does not end the affair, she said there is no single reason, but rather a combination of emotional factors that build up over time.

On Nancy bringing Howard to a party despite secrecy, she said it works for storytelling and reflects how Nancy is drawn back into a more dangerous version of herself that becomes addictive.

On confronting her mother’s former boyfriend, she said it felt brave because Nancy is facing someone who deeply violated her trust and abused power.

On Cora’s absence in episode five, she said their relationship was very tense and already deeply damaged before Nancy’s death.

On Robert’s violent reaction, she said she does not think he was always violent and that the series suggests he was not like that before.

On Robert’s insecurity about wealth, she said he defines himself through money, and losing it destabilizes him, while Nancy develops empathy for him once she understands this.

On Eleanor and Mary’s role in seeking justice, she said Nancy would likely have done the same for them, describing them as chosen family.

This interview has been edited and condensed.