Gil Pender is feeling very unfulfilled creatively, which is strange, because he is a very successful screen writer. He is engaged to a woman named Inez, who comes from a wealthy family who prioritize financial success over job satisfaction and have raised their daughter to do the same; consequently, when Gil struggles with his first novel she dismisses his ambitions to be a novelist as nothing but a frivolous daydream.
Gil has been thinking about moving to Paris, where by coincidence he and Inez are vacationing with her parents. Inez hates the idea; she wants to live in Malibu. Whilst they are in Paris they meet up with Paul and Carol, a married couple who consider themselves the authority on anything vaguely artistic or intellectual. Paul is overbearing in his confidence in his own brilliance and contradicts a tour guide at the Rodin Museum about Rodin's relationships a subject upon which, he feels, his knowledge is unmatched. Inez looks up to Paul but Gil finds him obnoxious and loathes his company.
Gil gets drunk at a wine tasting ad he walks back to the hotel, wanting to enjoy Paris by night, but Inez decides to take a taxi with Paul and Carol. At midnight, he sees a classic car from the 1920s pull up, and the car's passengers, who are all dressed in 1920s "flapper" clothing, ask him to join them. He does, and finds himself at a party for Jean Cocteau, his companions many notable people of the 1920s, including F. Scott Fitzgerald and Zelda. Perfectly normal - except for the fact that it is 2011. Zelda becomes bored with the party and when she and Scott leave they ask Gil to tag along. They go to Bricktop's to see Josephine Baker dance, and afterwards they find a little cafe where they find Juan Belmonte and Ernest Hemingway. Gil is excited to meet Hemingway; they talk about writing, and Hemingway offers to show Gertrude Stein Gil's partially finished novel. Gil rushes back to the hotel to fetch his manuscript, but as soon as he leaves the cafe he finds himself back in 2011. The cafe has gone; it is now a laundromat.
Gil wants Inez to come back in time with him, but she doesn't want to, and leaves him stranded before midnight, but when the clock strikes, the same care comes by him and Hemingway invites him to visit Gertrude Stein, and when they get to her apartment they find Pablo Picasso and his lover Adriana are already there. There is a definite sexual attraction between Gil and Adriana. Stein reads aloud from Gil's novel. The first line captivates Adriana. Gil loves his new group of friends. He meets them every night and Inez becomes increasingly irritated; she is also bored with the sidewalk cafes and bistros. Inez's father thinks Gil is having an affair and hires a private detective to tail him. Gil, meanwhile, has become one of Adriana's lovers, a distinction he shares with both Picasso and Hemingway. He feels terrible, but loves the attention he receives from her, and shares this conflict with Salvador Dalie, Man Ray and Luis Bunuel. They are not much help; they are Surrealists and so they think that traveling through time is perfectly normal.
They all believe that Gil should channel his feelings about his relationship with Adriana into great art. Gil suggests a movie plot to Bunuel.
Meanwhile, back in 2011, Inez and her parents take a trip to Mount St. Michel, whilst Gil meets an antique dealer called Gabriel, another devotee of the 1920s. He purchases a gramophone record by Cole Porter. He also finds Adriana's diary from the 1920s on an antique book stall by the side of the River Seine. He reads in the book that she was in love with him. She dreamed of making love to him, and receiving a pair of earrings as a gift from him. Wanting to fulfill her dreams for her, Gil tries to take a pair of Inez's earrings to give to her, but Inez comes back to the hotel room before he can get a hold of them. Thwarted, he buys her some earrings, and when he runs into her at a party, he gives them to her. Whilst she is putting them on a carriage pulls up and the couple riding in it invite Adriana and Gil to join them at a party. They ride into the Belle Epoque, a time that Adriana considers to be the Golden Age in Paris. They meet Edgar Degas, Henri de Toulouse-Lautrec and Paul Gaugin at the Moulin Rouge and they talk about the Renaissance which the three artists believe to have been the greatest time in history. Adriana is offered a job as a ballet costumier. She wants to stay at the party, and in the time, but Gil sees too many people around him searching for a golden age that has gone before. The realization wakes him up. Anything can be dull and pedestrian if you stop appreciating it. He decides to leave, but Adriana wants to remain in the 1890s, and so they go their separate ways.
Gil gets the draft copy of his novel back from Gertrude Stein, who tells him that it is good, and that Hemingway is enjoying it. However, she doesn't understand why the protagonist (who is based on Inez) would be having an affair with a dullard (based on Paul.) When Gil returns to 2011 he asks Inez about her relationship with Paul, and she admits that they have slept together, but tells him that it means nothing at all. Gil breaks up with her and decides that he is going to stay in Paris. Inez's father tells Gil that he had hired a detective to follow him but the detective has not been seen or heard from in several days. It transpires that the detective travelled back to the time of Louis XIV and that the last reported sighting of him was being chased by palace guards.
Gil walks by the Seine again at midnight, running into Gabrielle. When they talk, they find that they both love walking at night in Paris, because they find that it is at its most beautiful in the rain.
