Mr Dundas and his wife prepare to move into the Kintbury vicarage, and the urgent question of Isabella's future continues to occupy Cassandra as she learns the truth about Isabella and Lidderdale's past. Dinah makes a reckless decision. The letters reveal her sister's struggle to keep writing, as the family's fortunes – and Jane's mental and physical health – went into an alarming decline. Amid these very private recollections, young Cassandra's own letters tell a heartbreaking story of just how much she sacrificed to support her sister.

At Kintbury, Cassandra's fever is raging. In her delirium, she nearly lets slip that she is in possession of Jane's letters, but manages – just – to keep Mary from finding them. As she travels in and out of consciousness, Cassandra relives the dramatic events of her youthful summer in Sidmouth, where Mr Hobday's attentions are received with delight by the Austens but present Cassy with an impossible decision.

After uncovering Mary Austen's lies, Cassandra's determination to keep Jane's letters private is stronger than ever. Her mission is accompanied by a second – to secure a home for Isabella, who, following the death of her father, is being forced to leave the vicarage.

Intimations of a past romantic rivalry between young sisters Cassandra and Jane threaten to emerge. The older Cassandra denies any such thing, but as she delves into Jane's old letters, she secretly re-lives the youthful days of her and Jane's first encounter with Henry Hobday.

1830. A letter arrives at Chawton Cottage, where Cassandra Austen has lived alone for many years since the death of her sister Jane. The letter is from Kintbury, once the home of Jane and Cassandra's dearest friend Eliza.

Cassandra, now in her fifties, travels back to the village of her youthful memories to tend the deathbed of Eliza's husband, the Rev Fulwar Fowle. Once there, and despite a cool reception from sister-in-law Mary, she soon forms a strong bond with Eliza's daughter, Isabella. But it soon transpires that Cassandra has an additional motive for having returned to Kintbury – the retrieval of some mysterious and important personal items that she knows are held somewhere inside the vicarage...