Vida Winter, a famous novelist in England, has evaded journalists' questions about her past, from simply refusing to answer their inquiries to spinning elaborate tales that they later discover to be false. Her entire life is a secret, and for over fifty years reporters and biographers have tried innumerable methods in an attempt to extract the truth from Winter. With her health quickly fading, Winter enlists Margaret Lea, a bookish amateur biographer, to hear her story and write her biography. With her own family secrets, Lea finds the process of unraveling the past for Winter bringing her to confront her own ghosts.
The novel opens as Lea returns to her apartment above her father's antiquarian bookshop and finds a hand-written letter from Winter. It requests her presence at the author's residence and offers the chance to write Winter's life story before she succumbs to a terminal illness. Lea is surprised by the proposal, as she is only vaguely aware of the famous author and has not read any of the dozens of novels penned by Winter.
While considering the offer, Lea's curiosity prompts her to read her father's rare copy of Winter's Thirteen Tales of Change and Desperation. She is unexpectedly spellbound by the stories and confused when she realises the book contains only twelve stories. Where is the thirteenth tale? Intrigued, Margaret agrees to meet with the ageing author—if only to discuss her reasons for not accepting the position as Winter's biographer.
During their meeting at Winter's home, Lea attempts to politely decline the offer and leave, but is stopped at the door by the pleas of the older woman. With promises of a ghost story involving twins, Winter desperately implores the bibliophile to reconsider. By the end of the encounter, Lea finds herself increasingly drawn to the story and proposes a conditional agreement to Winter; to earn the trust of her biographer, Vida Winter must supply her with three verifiable truths. Somewhat reluctantly, the three secrets are extracted from their keeper. Afterwards, Winter and Lea begin their adventure into the past with; "Once upon a time there were two little girls...".
As Vida Winter tells her story to Lea, she shares dark family secrets which have long been kept hidden. She recalls her days at Angelfield (the estate that was her childhood home), which has since burned and been abandoned. Recording Winter's account (the author allows no questions), Lea becomes completely immersed in the strange and troubling story. In the end, both women have to confront their pasts and the weight of family secrets, as well as the ghosts that haunt them both.