On a fall day in New York City, 17-year-old Natasha Kingsley and her family prepare to leave the country. Because of her father’s DUI, they only have 12 hours left in the United States before being deported to Jamaica.
Natasha’s father, an actor, drank with the cast and crew after a performance and crashed into a police car on the way home. In a drunken confession, he told the officer that he and his family were in the United States illegally. Natasha, who immigrated when she was 8 years old, is afraid to be sent back to a country she does not remember.
At the same time, 17-year-old Daniel Jae Ho Bae leaves his family’s home to get his hair cut for an interview with a Yale college alumnus. Daniel is being pressured by his Korean-native parents to get accepted into Yale, especially now that that Daniel’s brother, Charlie, has been forced home from Harvard after having two semesters on probation. Despite his parents’ expectations, Daniel does not want to go the interview, go to Yale or become a doctor. He decides that until his interview later that day, he will do whatever the world tells him to.
In a last ditch effort to stop the deportation, Natasha goes to the U.S. Customs and Immigration Services (USCIS) but is delayed by Irene, a lonely security guard, who has decided to commit suicide after she’s done with work. Desperate for human connection, Irene meticulously processes Natasha’s personal belongings through security, pausing to touch and examine everything. Because Irene works so slowly, Natasha misses her appointment, but ends up meeting with another USCIS agent who gives her the phone number for immigration lawyer Jeremy Fitzgerald.
While Daniel is on the way to his haircut, the subway conductor stops the train and shares his testimony of salvation with passengers. He urges them to find God before they reach their final destinations. Daniel, who believes in fate, destiny and signs, decides he will look for signs from God. That’s when he sees Natasha. She is wearing a leather jacket with the words Deus ex machine (God from the machine) printed on the back. He spots her just before she goes into a record store called Second Coming.
Daniel takes this as a sign and goes into the store to talk to her. Natasha is preoccupied with her family’s situation and doesn’t want to get to know Daniel, but he follows her out of the store and pulls her from a crosswalk before a car hits her.
Natasha is shaken by the near accident and agrees to have coffee with Daniel. As they talk, they realize they are attracted to one another, but they are very different. Natasha relies on science and logic, while Daniel is a poet and a creative and passionate individual.
Daniel sees their meeting as being fated, and Natasha warns him not to fall in love with her, as she knows she may be leaving the country at the end of the day. Daniel tells her that falling in love can be scientific, as researchers have proven that two people can ask each other a series of personal questions followed by staring into each other’s eyes and fall in love.
Natasha agrees to the experiment. As the day unfolds, the two spend every moment possible together and get to know each other on a personal level. Daniel runs an errand at his family’s store. Although he has reservations about taking Natasha inside, he braves his father’s and brother’s reaction to seeing him with a Jamaican girl. His fears are justified as his brother makes racist and sexist comments, and his father is racially insensitive.
Daniel is deeply embarrassed. After they leave, he apologizes to Natasha. Despite the awkward and embarrassing situation, Natasha is happy that Daniel chose to be seen with her, even though it was difficult.
Daniel takes her out to lunch at a Korean restaurant and then to a norebang, a karaoke place with private rooms. They sing for each other and then kiss passionately. Natasha is surprised by the intense attraction between them, and it makes her nervous. The kiss only confirms Daniel’s belief that they are meant to be together.
They leave the norebang, and when Daniel mentions that they are fated, Natasha tells him that she will be deported. Daniel is angry at her for not telling him earlier, before he fell in love with her. They argue and go their separate ways. Daniel goes back to the family’s store and confronts his brother. The two get into a fight. Daniel’s father tells him that he should forget Natasha as she and Daniel can never be. Daniel leaves to find Natasha, deciding that he wants to be with her even if today is all they have.
Natasha meets with Jeremy Fitzgerald, who tells her that he is the best immigration attorney and will meet with a judge to get their deportation order overturned so they won’t have to leave that night. Natasha has hope for her situation and regrets how she and Daniel parted.
She goes back to his family’s store and convinces Charlie to give her Daniel’s phone number. She calls Daniel, and they meet at the building that Fitzgerald works, which happens to be the same building where Daniel’s interview is scheduled.
They learn more about one another and begin to influence each other’s decisions. Daniel realizes that he doesn’t have to follow his parents’ path; he can choose his own. Natasha begins to consider finding passion in her life the way Daniel does in his. Although Daniel considers their meeting an act of God, Natasha does not believe in God — though she wants to believe in things like love. They spend the time before Daniel’s interview talking, kissing and realizing they have fallen in love.
Natasha, finally believing in things that are meant to be, calls USCIS and leaves a message of thanks for Irene. She believes the morning’s delay started a series of events that led her to meeting Daniel and the meeting with Attorney Fitzgerald.
Daniel’s interview turns out to be with Jeremy Fitzgerald, who is ultimately unable to help Natasha. At the end of the day, Natasha and her family must get on a plane to return to Jamaica. Both Daniel and Natasha are heartbroken and promise to stay in touch, but time and distance cause them to lose touch.
Ten years later, Irene is now a flight attendant. She received Natasha’s message of thanks and decided not commit suicide, but to seek help for her depression instead. Irene sees Natasha on a flight, recognizes her and thanks Natasha for leaving the message all those years before. Their interaction catches the attention of Daniel, who happens to be sitting a few seats away. Natasha and Daniel recognize one another instantly.