Plot Summary: One night, Alfie (Anthony Hopkins) wakes up with a sudden wave of panic over thoughts of mortality. Abandoning Helena (Gemma Jones), his wife of forty years, Alfie sets out to relive the pleasures of his youth. Devastated, Helena tries to kill herself, and then, finding no consolation from medicine and therapy, seeks out the help of a fortune teller, Cristal (Pauline Collins). Before long, Helena finds the tranquility she seeks by surrendering all her thoughts and actions to Cristal's guidance.
Helena's daughter Sally (Naomi Watts) encourages her mother's pacifying visits to the charlatan fortune teller, as she is weary of dealing with her mother's trauma, and has marital problems of her own. Her novelist husband Roy (Josh Brolin) is unable to hold a paying job and the couple live off of Helena's support and Sally's earnings as an assistant to a prominent gallery owner, Greg Clemente (Antonio Banderas). Years ago, Roy produced an acclaimed first novel, but his subsequent books haven't lived up to his initial promise. Roy's fears that he may be a flash in the pan make him hard to live with and they clash over Sally's desire to have a child.
ears pass, and as Roy struggles to complete his latest novel, he becomes obsessed with a mysterious young woman in a red dress, who plays her guitar from a nearby window. Just as he is completing his book, a friend, Henry Strangler (Ewen Bremner), gives him the manuscript of his first novel. Roy recognizes that Strangler possesses the literary talent that has always eluded him.
Cristal tells Helena that she will be finding new love with a handsome stranger. Roy, annoyed by Helena's frequent visits, tells her that the dark stranger she will meet is the one everyone eventually meets. Sally accompanies Greg to a jewelry store to help him choose earrings for his wife, a task Sally does and envies Greg's wife, the life she leads with Greg.
While Alfie's pursuit of a second youth proved to be more challenging than he had hoped, one day he announces to Sally and Roy that he has found a woman, fallen in love, and is going to marry her. When Sally and Roy meet Alfie's fiancée, Charmaine (Lucy Punch), they discover her to be decades younger, very attractive, and utterly frivolous. Alfie fails to mention that he met Charmaine when he was paying for her services as a call girl.
To keep Helena occupied, Alfie had previously gotten her a job as a personal shopper for Enid (Celia Imrie) and Peter Wicklow (Jim Piddock). While at the Wicklow home, she meets Peter's uncle Jonathan (Roger Ashton-Griffiths), a recent a widower who runs an occult bookshop.
While not exactly handsome or tall, Jonathan is at least a stranger, and Helena starts keeping company with him.
As Roy anxiously awaits a response to his manuscript from his editor, Malcolm Dodds (Alex Macqueen), he invites the woman in the window for lunch. Seeing the woman, whose name is Dia (Freida Pinto), at close quarters for the first time, he discovers that she is both breathtakingly beautiful and soon to marry. Roy flirts brazenly with Dia, and she doesn't discourage him.
Sally takes Greg to visit the gallery of a painter friend that she believes in as an artist, Iris (Anna Friel). Greg is impressed with her work and agrees to represent her.
Greg has opera tickets for the evening, and as his wife can't go, he invites Sally to come with him. Afterwards, as Greg drops Sally off, he thanks her for coming with him, listening to his marital woes, and for all the help she gives him at the office. It's clear that Sally is developing a crush on her boss, but his interest in her is hard to gauge.
The passing days bring about impending troubles and disappointments: Alfie is increasingly aware he can't afford the luxuries he is showering on Charmaine: Sally is disheartened to find out that Greg is having an affair with Iris; and worst of all, Roy's book is rejected and he sees his world collapsing. Roy can't imagine living without writing, and he knows that without success he will never be able to support a life with Dia.
Just as Roy seems to have no way out, he hears that that two of his friends have been in an accident—Mike is in a coma and Strangler is dead. Certain that Strangler hasn't shown his book to anyone else, Roy breaks into Strangler's apartment and steals his manuscript.
Won over by Roy's persistent courtship, Dia cancels her marriage shortly before the ceremony, creating uproar in her family and her fiancé Alan's (Neil Jackson) family. With Dia now free and with the acclaim for Strangler's manuscript, Roy gets both the woman of his dreams and the literary success he had always yearned for.
Helena and Jonathan are getting more serious but as he believes in the afterlife, the two of them attempt to secure his dead wife's permission to marry at a séance. Now that Sally has the emotional burden of Roy out of her life, she decides to start up her own gallery with her friend Jane (Fenella Woolgar), and Helena agrees to bankroll her. As she'll no longer be Greg's employee, Sally feels the time is right for her to make her romantic feelings known to him. Finally, after discovering that Charmaine has been cheating, Alfie finally comprehends the calamity his behavior has brought for Helena and for himself, and decides to do something about it.
Just as the characters seem to be drawing towards resolutions of their problems, they learn there are no easy ways out. In fact, amid all their disappointments, it may only have been their fantasies that have kept them going. Through the stories of the characters in "You Will Meet a Tall Dark Stranger" Woody Allen explores the human need to elude life's adversities by nurturing illusions.