NOTE: This spoiler sent in by ValleyVillage.
Poor Harvey Shine (Dustin Hoffman) is a would-be jazz pianist to whom fate has given the job of jingle writer for a Manhattan agency. We see him at work and get the feeling he is good at what he does, really understands the needs of the clients, but doesn't really consider what he creates to be "music."
His boss does not seem any too impressed with his latest output and actually suggests that he spend more time in England, where he is headed for his daughter's wedding, than he had originally planned. Harvey declines, making the point that he needs to be back there for an upcoming pitch to an old client.
He departs for England, planning on a rapid turn around. His boss is not so sure.
On the way across the pond, Harvey tries to chat up a fellow passenger, but she's having none of it. He's left sitting there with egg on his face, and we come to regard him as even more of a loser.
When he arrives at the airport in London, an interviewer attempts to question him about his reasons for visiting the UK, but Harvey rebuffs her attempt. He's not in a good mood and really is rather rude to her.
The interviewer is Kate Walker, played by Emma Thompson, and we get the message: he'll be seeing more of her.
Harvey heads for the hotel only to discover that everyone else is staying at a lovely home belonging to one of the wedding party and only he is being put up at a hotel. His feelings are further crushed when his daughter informs him that she would rather have her stepfather walk her down the aisle.
Poor Harvey learns this at the rehearsal dinner. He has worn a white suit, thinking this was requested. It wasn't and he's the only one so dressed and he feels even more foolish when he realizes the anti-shoplifting device is still attached to the sleeve.
It is obvious that he can't wait to get the wedding over with and then hurry back to NYC for the big meeting. He tells his daughter he won't be coming to the reception because of this date.
Meanwhile, we learn a little more about Kate Walker. She works for the company at the airport, gathers demographics about arriving passengers, and deals with her slightly dotty Mum, played by Eileen Atkins. Her mother is convinced that the foreigner living next door is some kind of murderer because she sees him toting strange looking, lumpy packages into a shed in the back yard.
After the wedding Harvey finds himself in a traffic jam on the way to the airport. He arrives with only minutes to spare, but is informed the plane has already closed to boarding. He calls his boss in NYC to inform him that he'll try to get there as soon as possible, but is greeted by the news that he's been fired.
In this glum mood he makes his way to the airport bar and starts slugging down Scotch.
Kate Walker is sitting in the lounge eating lunch, reading a novel, and notices Harvey...the only other person in the bar. She makes some sort of comment about the drinking will be a big help to what ever is bothering him and he fires back some barb about her reading a bad novel.
But they gradually warm to each other over the course of their "lunch" and eventually, after several on again off again attempts, Harvey convinces Kate to spend some more time with him. She agrees, but he needs to wait for her to attend her writing class.
This he does willingly.
In fact they are getting along so well that Kate feels moved to insist that Harvey attend the wedding reception. Harvey decides he will, but only if Kate goes with him!
She protests that she has nothing to wear, but Harvey takes her shopping. They settle on a lovely outfit and head to the reception.
Harvey makes a moving toast to his daughter, one that makes everyone, including the audience, love him even more. Of course, Kate is falling in love with him too.
They stay together until the dawn, and then make a date to meet each other at noon! They are both excited about the upcoming rendezvous, but Harvey suffers an attack of arrhythmia because the hotel's elevators are out of order and he runs up the stairs too quickly! Paramedics rush him to the hospital.
Harvey can't show up for their meeting and Kate is crushed and rueful.
Harvey manages to get out of the hospital and heads to the airport to redeem himself with Kate but she's not there! Her workmates are suspicious of him at first but later decide they should end up together and let him know that she's at her writing class.
Harvey hears from his boss and all is forgiven! He still has the job and should come right back. Harvey declines, indicating that he has better things to do.
He arrives at Kate's writing class and when she sees him waiting for her she is by turns angry, sad, and understanding. He insists on explaining what happened and it becomes clear that these two have a future together. Happy ending!
By way of a final fillip, the credits reveal that the next-door neighbor of Kate's mother is smoking meat, and he brings Mrs. Walker a ham. There is more than a hint that these two may be the next to succumb to Cupid's arrow.