Note: The synopsis below includes plot details, including the ending.

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HELEN OF BOSTON opens with forty-nine-year-old Helen Kersey sitting in an oncologist’s office, absorbing a diagnosis of early-stage lung cancer. Although the prognosis is optimistic, the news arrives on the heels of another blow: She has recently learned that her husband, Gray, is having an affair. Facing illness, betrayal, and the unsettling realization that she is approaching fifty with the balance of her life behind her, Helen begins an emotional reckoning she can no longer postpone. Before leaving the oncologist’s office, she pockets one of a collection of masks displayed on the wall—a dark, otherworldly bird mask—an impulsive act that feels less like theft than an attempt to reclaim some small measure of control.

Seeking distance and clarity, she travels from Boston to San Francisco to attend the wedding of one of her closest college friends, Etta, with whom she once studied journalism. Both Etta and Nick, another close friend from that period, have gone on to become globe-trotting journalists, fulfilling ambitions Helen once shared. At the wedding, Helen reconnects with Nick, her first love, whose move to New York after college quietly ended their relationship and the life she once imagined for herself. Their reunion is charged but uneasy: Nick is openly critical of Helen’s marriage to a wealthy man and the comfortable, constrained life she has built. Helen bristles at his judgment, even as she recognizes its truth.

Still raw from Nick’s criticism, Helen makes an impulsive, uncharacteristic decision: she wears the stolen bird mask to an exhibition opening at the San Francisco Museum of Modern Art where Nick and other members of the wedding group are in attendance. She keeps it on as a quiet act of rebellion. The mask gives her courage she does not recognize in herself, and Nick, startled by her defiance, sees her anew. The night ends in his hotel room, where the two share a brief romantic encounter that is interrupted when Helen suffers a violent coughing fit and begins coughing up blood. Nick rushes her to the emergency room, where she spends the night under observation. The following day, Gray calls after learning of the hospital visit through their insurance company. Forced into honesty, Helen reveals her cancer diagnosis; Gray, in turn, confronts her about why she kept it from him. Helen responds by acknowledging his affair, bringing months of silence and deception into the open.

Nick persuades Helen to allow him to travel with her back to Boston a day early so they can continue the conversation cut short in San Francisco. Once in Boston, they take a hotel room together and sleep together, an act that ultimately feels to Helen less like romance and more like an attempt to reclaim a version of herself she abandoned long ago. Later that evening, they run into Gray by chance outside a restaurant. The encounter is tense but civil, and Helen’s infidelity is now, too, exposed. Gray confronts her privately, but they agree to delay any decisions until after her upcoming surgery.

Helen’s cancer surgery is successful, and during her recovery she and Gray slip back into the rhythms of their former life, avoiding discussions of either his affair or her night with Nick. Outwardly, everything appears stable, but internally Helen feels increasingly unmoored. She is torn between the safety and comfort of her marriage and a growing hunger for the passion, creativity, and purpose she once felt when she was younger.

At the urging of a close friend, Helen travels alone to a retreat center in the Berkshire Mountains of Western Massachusetts. There, she befriends Carla, a blunt woman from Texas who lives with her mother and works at an Amazon warehouse. Carla’s unsentimental honesty and lack of deference to social hierarchies challenge Helen’s habitual passivity and politeness. Through their conversations, Helen begins to confront a long-buried grief: the death of her mother when Helen was sixteen, a loss she has never fully examined or integrated.

While at the retreat, Helen unexpectedly comes face-to-face with Whitney, the woman with whom Gray had been having an affair, now involved with another of Gray’s colleagues. Empowered by Carla’s influence, Helen confronts Whitney directly. The exchange marks a turning point, as Helen speaks plainly and without apology, asserting herself in a way she never has before.

Leaving the retreat changed, Helen decides not to rush home. Driving back to Boston along back roads, she stops in Northampton, Massachusetts, home to Smith College. Struck by the town’s intimacy and intellectual life, Helen allows herself to imagine a different future. In a local pub, she meets an older man who bitterly disparages the idea of leaving Boston for a smaller life; for the first time, Helen chooses not to accept a man’s opinions as truth. Acting on impulse, she applies for a writing position at Smith.

The college responds with a test assignment: Helen must write a feature about a Smith alumna who runs a small nonprofit serving people experiencing homelessness in downtown Boston. Spending a day with the alumna, Helen is deeply moved by her independence, sense of purpose, and commitment to meaningful work. Writing the piece reignites Helen’s long-dormant creative self, reminding her that storytelling, not prestige or comfort, was always what she wanted.

When weeks pass without word from Smith, doubt creeps back in. During Thanksgiving at the lavish home of one of Gray’s colleagues, Helen briefly finds herself seduced again by the ease of her life. That illusion collapses when the colleague’s wife casually reveals that the group of wives has long known about Gray’s infidelity and accepts such betrayals as inevitable. Helen suddenly sees the world she inhabits as hollow and profoundly limiting.

In the novel’s final movement, Helen is offered the job at Smith. She returns to her hometown of Hull, Massachusetts, visiting the seaside bar where she once worked as a teenager, and reflects on the losses, compromises, and choices that shaped her life. She calls Nick and closes the door on their connection, recognizing that their relationship belonged to a version of herself that no longer exists. Helen then tells Gray she is leaving him. She prepares to move to Northampton, stepping into a future defined not by marriage, nostalgia, or fear, but by work, self-determination, and a newly integrated sense of self.

In the epilogue, Helen returns to the oncologist’s office for a follow-up appointment; after the doctor leaves the room, she carefully replaces the bird mask back on its hook.