Based on the surviving letters from Jane Austen to her sister Cassandra, and her young niece Fanny.[5] In the unknowingly last few years of Jane's life, with her 40th birthday coming up, she is asked by her niece Fanny (Poots) to go over what makes a good potential husband. Jane recalls when she was 27, a rich neighboring landowner, Harris Bigg-Wither (Roukin), proposed to her which she accepted. But after a long night of soul searching, Jane turned him down the next day which caused her and her family to live in genteel poverty, something her mother never let her forget. Jane confirms that that was the circumstance that put her off to the idea of marriage. Although she never married, she remembers the one who got away, Reverend Brook Bridges (Bonneville) who couldn't wait any longer for Jane and ended up marrying someone else.[3][5] Jane's aversion to marriage subsequently talks Fanny out of furthering her relationship with John Plumptre (Hiddleston) which then causes him to marry someone else. With Fanny being upset with Jane, Jane decides to tell Fanny of her lost love to get her to better understand that she knows what Fanny's going through.