Wallis "Wally" Winthrop is a young American housewife living in New York City in 1998. Although she is neglected, abused, and left sexually frustrated by William, her workaholic psychiatrist husband, she is comforted by the love story of Edward VIII and Wallis Simpson. Wally travels to the Sotheby's auction of the Windsor estate, which showcases items used by Wallis and Edward in their lifetime and evokes their relationship.
In 1930, Edward throws a party at his new home at Fort Belvedere in Windsor Great Park and meets Wallis through Lady Furness (his mistress). They are attracted to each other (despite Wallis' marriage to Ernest Simpson), and become lovers while Lady Furness is abroad. At Sotheby's Wally is interrupted by a guard, Evgeni, who is interested in her.
Edward and Wallis continue their affair while touring Europe, where he gives her jewels and adopts the initials W.E. By the end of 1934, Edward is obsessed with Wallis. He introduces her to his parents, King George V and Queen Mary, but she is criticized by Edward's sister-in-law Elizabeth. A distraught Wallis wants to end the relationship, but Edward pacifies her.
In New York, William refuses to conceive a child with Wally and she turns to in vitro fertilisation. Attracted to Evgeni, she goes on a date with him. Wally asks Evgeni about Edward and Wallis' story, pondering her relationship with William. After attending the auction at Sotheby's and spending ten thousand dollars, Wally returns home to a drunken William and they fight.
The National Government refuses to recognise Edward and Wallis' relationship because she is a divorcée. On the night of December 11, 1936, Edward announces by radio to the nation and the Empire that he is abdicating the throne in favour of his brother Bertie: "I have found it impossible to carry the heavy burden of responsibility and to discharge my duties as King, as I would wish to do, without the help and support of the woman I love." Wallis, who has fled to Villa Lou Viei near Cannes, hears the speech and reconciles with Edward.
Evgeni desperately tries to phone Wally. Racing to her apartment, he finds that she has been injured by William and brings her to his home in Brooklyn. As she recovers, Wally finds new hope with Evgeni and the courage to divorce William.
Reading a series of letters in billionaire Mohamed Al-Fayed's collection, Wally realises that Wallis was trapped in her relationship with Edward for the rest of her life. In an imaginary dialogue with Wallis, they discuss the similarity of their lives; in the end, only Wally finds happiness. Abandoning her fascination with Wallis and Edward's relationship, Wally learns from her doctor that she is finally pregnant.
Abbie Cornish as Wally Winthrop
Andrea Riseborough as Wallis Simpson
James D'Arcy as King Edward VIII
Oscar Isaac as Evgeni
Richard Coyle as William Winthrop
David Harbour as Ernest Simpson
James Fox as King George V
Judy Parfitt as Queen Mary
Haluk Bilginer as Mohamed Al-Fayed
Geoffrey Palmer as Stanley Baldwin
Natalie Dormer as Queen Elizabeth
Laurence Fox as King George VI ("Bertie")
Douglas Reith as Lord Brownlow
Katie McGrath as Thelma, Lady Furness