Plot

The story of former Hollywood star Grace Kelly's crisis of marriage and identity, during a political dispute between Monaco's Prince Rainier III and France's Charles De Gaulle, and a looming French invasion of Monaco in the early 1960s.

1961. Princess Grace, the former Grace Kelly, has been married to Prince Rainier of Monaco now for five years, they having two young children. Her transition from famed Oscar-winning Hollywood actress from a background as the daughter of a wealthy millionaire owner of a brickworks in Philadelphia to European princess of a small, exclusive and tight-knit principality has been a difficult one, the Monagasques who have been less than welcoming to her in her outspoken American nature. Even in her official charity work as head of a women's committee for the Red Cross, the other committee members largely grumble under their breath about her as their leader. Despite loving Rainier, their marriage is a largely distant one emotionally as he focuses on his role as monarch, now an especially difficult time in the on-going tension between Monaco and France under the leadership of Charles de Gaulle, who would, if he could, annex Monaco back under French control. She has a small entourage of trusted advisers who lead her through the maze of her life, including an American Catholic priest, Father Francis Tucker, currently based in Monaco, and she bringing back into the fold Rupert Allan, who worked as her Hollywood publicist. Despite the unofficial roles of the members of this entourage, Grace has never had official guidance into all that it means to be Princess of Monaco. She has always been courted by the Hollywood community to continue acting, the thoughts of doing so stronger now than ever in her general unhappiness, with a concrete high profile role offered to her by her oft late career collaborator Sir Alfred Hitchcock. She returning to acting would be seen by the Monagasques and probably Rainier as she turning her back on her royal duties. What Grace decides to do under the circumstances takes into account her own happiness, the welfare of their two children who nonetheless will inherit the throne, whether she loves Rainier enough especially in light of an action by France, and whether she sees herself as Princess, and what she can do for the monarchy, the principality, and its subjects in light of her relationship with Rainier.—Huggo

Grace of Monaco is focused on former Hollywood star Grace Kelly's (Nicole Kidman) crisis of marriage and identity, during a dispute between Monaco's Prince Rainier III and France's Charles De Gaulle in 1962 as well as her considering a return to Hollywood to film Alfred Hitchcock's Marnie.

Rainier III, Prince of Monaco (Tim Roth), won Grace's hand in marriage in 1956 after a whirlwind romance. The entire Kelly family traveled to Monaco for the wedding, which was attended by the who's who of the world's royalty. Madge Tivey-Faucon (Parker Posey) is Grace's personal secretary & loyal to Rainier.

Alfred Hitchcock (Roger Ashton-Griffiths), approaches Kelly in December 1961, & offers her the lead role in movie Marnie, for which she will get $ 1 MM. Princess Antoinette of Monaco (Geraldine Somerville) is Rainier's sister. Rainier is worried that the state treasury is empty. Aristotle Onassis (Robert Lindsay) is a rich businessman who likes to curry favors with the royalty.

France is engaged in a bloody war in Algiers & wants Monaco to pick sides in the war & support the French above the Americans and the Russians. During a dinner hosted by Onassis, Grace insults the treasurer of France for his imperialist views on the colonies, when Rainier was looking for financial support from France. His is angry at Grace for speaking her mind. Countess Baciocchi (Jeanne Balibar) is a Manocan socialite & head of the local Red Cross, who consistently reminds Grace that the royalty is out of money & can't pay of any of the social projects that Grace cares about.

The Frech Govt headed by Charles De Gaulle (André Penvern) conveys to Rainier that France considers Monaco as a protectorate. 90% of new businesses opened in Monaco are French, due to its 0 tax policy. When Monaco intends to impose tax to fill its treasury, France wants Monaco to give that tax to France.

Rainier attacks the French negotiator, when he insults Grace's background, & in return Charles De Gaulle threatens war unless Rainier apologizes or pays. Grace decides to do the Hitchcock movie. Rupert Allen (Milo Ventimiglia) is the Universal Studios publicist. Mr. Delavenne (Yves Jacques) is the minister of Interior & objects to the venture, but reluctantly agrees when Grace & Allen decide to keep the news a secret till the French crisis blows over. But Delavenne & Madge leak the news to the press before the crisis is over, to make it impossible for Grace to do the project.

Grace confides in Father Francis Tucker (Frank Langella) that she only trusts Phyllis Blum (Flora Nicholson), the children's nanny, whom she handpicked. Rainier's negotiations with Charles De Gaulle go badly, & he wants revenge. Rainier asks Grace to turn down Hitchcock's offer publicly, at a family lunch & Grace refuses. The crisis deepens in August 1962, as the French army & navies surround Monaco with the intention of starving it. Best estimates suggest annexation by October.

Grace approaches Count Fernando D'Ailieres (Derek Jacobi) the protocol minister, to learn about Monacon history and culture. she gets better at French too. Fernando and Father Francis are told that since France cannot bar foreign diplomats from entering Monaco, Rainier has arranged a state banquet in September to gather military support from neighboring nations & Grace has to be ready by then.

Under Fernando's eyes Grace starts to increase her public appearances & starts to win over the people of Monaco & even the French border guards surrounding her country. Madge is found to spying for someone inside the palace. Father Francis receives an offer to move back to the US, that he is considering seriously. At the state banquet, things go well, but then news trickles in that there has been an assassination attempt on De Gaulle. This would make it impossible for the neighboring states to support Monaco now.

The same night Madge approaches Grace with photo evidence of Antionette meeting with the French govt officials, behind Rainier's back. Madge had hired a detective and that what er secret meetings were all about. Madge says that Antionette made a deal with France to deliver Monaco, in exchange for the throne.

The next morning Grace calls Hitchcock and refuses to do the role, saying she needs to perform her duties to Monaco. Grace enlists the help of Countess Baciocchi to organize an international red cross event in Monaco, inviting all heads of state, including De Gaulle. Grace & Rainier exile Antionette & her husband from Monaco but promise them their son's future if Antionette convinces De Gaulle to attend the red cross function. Antionette's husband makes the call & De Gaulle agrees to attend. The Us President Robert McNamara (Philip Delancy) is also invited. The French only care about the American opinion in their quest for Monaco.

At the ball, both De Gaulle & McNamara are witness to the Grace of Monaco & her stirring speech about the triumph of love over hatred. This changes McNamara's opinion & he mocks De Gaulle about bombing Monaco. In May 1963, France lifted the blockade and demands for taxation.