Molly Gilmore and Frank Raftis do not know each other, but they have parallel experiences as they take the Metro-North Commuter Railroad from Westchester County into Manhattan on the day before Christmas. At adjacent telephone booths in Grand Central Station, each calls family, then buys gifts for their spouses at Saks Fifth Avenue, and later visits friends. Over lunch, Frank’s friend and colleague, Ed Lasky, reveals he is getting a divorce, and Molly learns that her friend, Isabelle, is going to Acapulco with her young boyfriend, David. In the evening, Frank and Molly shop at the bookstore, Rizzoli. As they leave the store with multiple shopping bags, their paths collide, when Molly realizes that Frank has mistakenly grabbed her package. Frank gives it to her, and they wish each other a Merry Christmas. The next morning, Frank opens presents with his wife, Ann, and two sons, Mike and Joe, and after Ann unwraps The Big Book of Sailing, he is perplexed about what happened to the gardening book he bought her. Meanwhile, under Molly’s Christmas tree, her husband Brian Gilmore, receives the gift, Gardens for All Seasons, and she is amused by the mix-up. Three months later on the Metro-North Commuter train, Frank notices Molly and attempts to figure out why she seems so familiar. As they disembark, Frank recalls that she is the woman from Rizzoli, and reminds her about dropping the Christmas packages. Molly says that she still has his book. In a nod to their previous meeting, they wish each other a Merry Christmas and go their separate ways. At work on a construction site in Manhattan, Frank’s colleague, Victor Rawlins, encourages him to consider an opportunity in Houston, Texas, but Frank is reluctant to commit to the year-long job. Molly visits her father, John Trainer, in the hospital, but has difficulty getting a straight answer from him about his health. Back at the construction site, Frank tells Ed about a woman he met on the train that morning, and meanwhile at Isabelle’s office, while showing her latest illustrations, Molly mentions Frank. Despite their friends’s goading, Molly and Frank downplay any significance; however, prior to boarding the train, Frank practices a dialogue he might have with Molly. On the train, Frank sees Molly looking for a seat and later approaches her standing near the door where they have an awkward conversation about being married and the curious fact of running into each other again. Tactfully, Frank suggests that they ride together tomorrow, and, Molly tells him that she plans to take the Friday, 9:04am train. That morning, Frank just makes the train, and Molly saves the seat next to her. During the ride, he talks about his sons. Later that day, Frank arranges to meet Molly at the hospital and persuades her to have lunch, during which he does most of the talking. Although shy, Molly is engaged by his conversation and sense of humor. On another day, at a cafe in Grand Central Station, Molly speaks more openly, revealing that two years ago her newborn daughter died. Molly and Frank continue to get to know each during their commutes. Sometime later, while walking together in Manhattan, Isabelle suspects that Molly is seeing someone, based on her glowing appearance. Molly tries to explain that it is only a friendship, but her uneasiness indicates deeper feelings. Embarrassed, Molly abruptly walks away from Isabelle and telephones Frank. Molly and Frank spend that afternoon in Chinatown and have their picture taken together in an arcade photo booth. That evening during dinner with Brian, Molly appears preoccupied. On another day, Molly hurries to the hospital to learn that her father had an arteriogram, and requires heart surgery. Molly is unable to reach her husband with the news, so she telephones Frank and goes to see him at the construction site. Frank recognizes that something is wrong. At first, Molly explains that her father is back in the hospital, but then proclaims, with ambivalence, that she has responsibilities and should not see Frank anymore. As she gets into a taxi, Frank asks her to wait for him at the station cafe at 5:45pm, prior to boarding the train. Delayed by work, Frank hurries to the station, only to miss the rendezvous. As the train pulls away, he turns around to see that Molly is waiting for him on the platform. He passionately kisses her and expresses his love. The next day, instead of taking his sons to a baseball game, Frank meets Molly at Rizzoli. Despite their mutual doubts and anxiety, they go to Ed’s empty apartment in Manhattan. They kiss, but as they move to the bed and begin to remove their clothes, Molly says she cannot continue and apologizes. They hold hands on the train home. At the Dobbs Ferry station, Molly watches from the train as Frank’s wife and sons greet him. When she arrives home, Molly’s husband says her father has died, and Frank learns the news when he tries to telephone Molly at the hospital. Overcome with grief and guilt, Molly becomes hysterical during the funeral, and her husband has a difficult time calming her. At home in bed, she relates to Isabelle that she cannot stop thinking about Frank, and that Brian assumes Molly is just distracted by the death of her father. Molly admits to Isabelle that she loves Frank and believes they are meant to be together even though she is resigned to the fact that they never will be. While Ann fixes him dinner, Frank discusses the Houston job that he has finally accepted, but his wife senses that there is something else he is not telling her. Frank confesses that he met a woman on the train, but that it was only a friendship and nothing happened. Calmly, Ann says that she will take the kids to Denver for two weeks to see her mother, and then she slaps Frank. That evening, Frank drives to Molly’s house and looks at it from his car. The night of his departure for Houston, he telephones Molly at home and says he misses her, asking if they can meet that evening. Molly’s husband enters the room, making it difficult for her to talk openly, so she says goodbye, wishing Frank a good trip. After she hangs up, her husband says, “well, that’s that,” indicating he knows about Frank. Molly rushes out to catch Frank, despite Brian’s pleading. Frank calls Molly again before getting in the taxi, but Brian answers, lying to Frank that Molly does not want to speak to him. In the pouring rain, Molly speeds along the road, slamming on brakes to avoid a train and stalling her car, thereby missing the opportunity to say goodbye. The following Christmas, Frank is visiting from Houston and meets Ed at a restaurant in Manhattan. After Ed asks Frank to be the best man at his upcoming wedding, Frank reveals that he came back to arrange the sale of his house and that his marriage with Ann did not work out, so she returned to Denver. Meanwhile, Molly is also in Manhattan visiting with Isabelle, who encourages Molly to accept a job offer and insists that she should join her in Barbados, instead of spending Christmas alone. That evening, Frank enters Rizzoli and encounters Molly. During their polite but reserved exchange, Molly apologizes for not being able to say goodbye the night he left for Houston, and Frank says he should not have called. When asked about their families, neither discloses the state of their marriages. They wish each other a Merry Christmas and leave the bookstore, walking in opposite directions, but thinking about the other. Frank stops and runs down the sidewalk. At Grand Central Station, Molly boards the commuter train. During the journey, she sees Frank making his way towards her. They kiss, embrace, and stare into each other’s eyes.