As the episode unfolds in the year 1830, Mary (portrayed by Jessica Hynes) arrives at the serene confines of the Kintbury rectory, her tone tinged with sardonic amusement as she teases Cassandra (Keeley Hawes) yet again for keeping her visit to the village a well-guarded secret. The conversation shifts to the delicate matter of Jane's letters intended for Mary's sister Eliza, which Cassandra has been covertly perusing. With a lie that glimmers like a polished deceit, Cassandra denies having stumbled upon them, prompting Mary to vow to search for them herself, determined to uncover the truth.
Elsewhere, Mary’s niece, Isabella (played by Rose Leslie), Eliza’s heartbroken daughter, is still grappling with the sorrow of her father’s passing and the impending reality of leaving the rectory’s comforting embrace. Cassandra, her voice imbued with genuine empathy, tries to steer Isabella towards resolving the uncertainty of her future by suggesting a visit to her sisters, among whom she might find a new home. However, Isabella hesitates, her reluctance palpable.
As Cassandra's thoughts revert to the letters, a series of poignant flashbacks reveal a younger Cassandra – Cassy (Synnøve Karlsen) – still reeling from the tragic loss of her fiancé Tom, yet striving to maintain a brave façade. Seeking solace, she journeys to Kent to stay with her brother Edward (Hubert Burton) and his family, only to find herself in Jane's (Patsy Ferran) suspicious gaze, who fears she is being used merely as an overglorified nanny.
Back in the present day of 1830, Cassandra pays a visit to Isabella’s quirky sister Mary Jane (Florence Bell), who declares with unexpected finality that Isabella will be joining her, citing her own inability to manage alone. Cassandra, however, notes with concern that Isabella seems blissfully unaware of this prearranged arrangement. Meanwhile, Isabella chance encounters the local physician, Mr Lidderdale (Alfred Enoch), and together they navigate an awkward conversation about her uncertain future plans, each word heavy with the weight of impending change.As the flashbacks unfurl once more, Cassy remains ensconced within the confines of Edward's abode, while Jane harbors concerns that her sister is ensnared there, fearing she might be condemned to the fate of a spinster aunt. In a bid to liberate Cassy from this potential quagmire, Jane enlists the aid of her friend Eliza (portrayed by Madeleine Walker) to extend an invitation for Cassy's assistance as she approaches her confinement at Kintbury. Cassy proves to be an invaluable pillar of support during the birth of baby Isabella, her presence a shining beacon of strength.
Fast forward to 1830 once again, and Cassandra is deeply impressed by the sight of adult Isabella, now instructing a young lad with palpable passion. Loyal Dinah (Mirren Mack), the ever-observant maid, hints at depths to Isabella's character unseen by the casual observer and reveals the overshadowing presence of her domineering father within their household. Impelled by curiosity, Cassandra ventures out to visit Isabella's sister Beth (Clare Foster), a teacher whose village school has been shuttered. She discovers Beth lending a helping hand to Dr. Lidderdale in nursing a diphtheria-stricken woman. However, as Beth and Cassandra delve into Isabella's future prospects, Beth's reluctance to become entangled becomes plainly evident.
Returning home, Mary is incensed at her continued inability to locate the elusive letters and scolds Cassandra for venturing out into the inclement weather. Determined to assert firmer control over the family dynamic, Mary also presses Isabella to move past her father's loss. Cassandra, ever the mediator, inadvertently stirs further tension by remarking on the apparent familiarity between Beth and Mr. Lidderdale.
In an attempt to elevate the somber mood, Cassandra reads aloud from Jane's novel, "Persuasion," capturing Isabella's eager attention as she yearns for a romantic denouement culminating in a blissful union. Cassandra gently reminds her that happiness can manifest in myriad forms, prompting Isabella to inquire whether Jane herself ever experienced love. Cassandra asserts that no man has ever measured up, only to be interrupted by Mary's stunning revelation of a past romantic rivalry between the sisters. Cassandra vehemently disputes this claim, retreating to bed feigning illness, the air thick with unresolved tensions.
In the recurring flashbacks, the Austen family finds themselves in the picturesque town of Sidmouth, nestled in the heart of Devon. There, Cassy, now an eternal figure draped in mourning black, ventures out with her young niece Anna (Vivien Battley) to a bustling fabric shop. It is within this vibrant setting that Cassy's hand happens to brush against that of a dashing gentleman who has come to collect his mother. Anna later recounts their serendipitous encounter to Jane, who is captivated by the tale, whereas Cassy dismisses it with a shrug.
On a leisurely stroll with their mother, Mrs. Austen (Phyllis Logan), the Austen sisters, accompanied by Anna and Mr. Austen (Kevin McNally), encounter the gentleman once more. He introduces himself as Henry Hobday (Max Irons), a name that seems to resonate with promise. When they chance upon him again on the sandy shores, Mrs. Austen's eyes sparkle with excitement, envisioning him as the perfect suitor for Cassy. Cassy, however, playfully suggests that he would be an even better match for Jane.
During a delightful tea gathering with Henry's mother, Mrs. Hobday (Rebecca Johnson), she lavishes praise upon her son. Following a visit to the local church, Henry engages in animated conversation with the Austens, particularly taken by Jane's candid opinions. Later, when Cassy and Jane delve into their discussion, Jane insists that Henry harbors a deep fondness for Cassy. Cassy, however, remains steadfast in her belief that she has lost the one man destined to be her husband – Tom.
Undeterred, Jane, with Anna's cunning assistance, procures a radiant yellow dress for Cassy, aiming to lift her out of her somber attire. At a beachside picnic, Henry takes Cassy for a serene stroll, where he expresses genuine sympathy for her loss. Cassy, confiding in him, admits that her grief once felt crippling but is gradually losing its edge. In a heartfelt letter to Eliza, Jane reveals that Cassy's heart has found new love.
Flashing back to 1830, Cassandra is deeply distressed by what she has read of their past. In a rush of emotions, she hastily stuffs the letters into a drawer before collapsing to the floor, overwhelmed by illness.
