The film is based on the novel of the same name written by Pamela Wallace and published in the Silhouette Special Edition line of romance novels in 1985 by Simon & Schuster before the Silhouette brand was acquired by Harlequin. There are alterations to the plot line made by the screenwriter but the essential story has stayed the same. The action and events take place in two time periods in England, the 1940s and the 1980s. The World War Two story is told in flashbacks.
Jessie Cantrell's dying wish is that her daughter Casey (Sharon Stone) personally take a letter to Lord Richard Bredon who lives in the UK. Viewing the matter as a sacred trust Casey sets off for England from her horse farm in Kentucky. A failed attempt to find him at his country residence has her falling from a wall into the arms of Lord Bredon's playboy son, Michael (Christopher Cazenove). Casey manages to escape his grilling without giving her name, but the younger Bredon tracks her to an inn in the local village where he uses his clout to get it.
Casey accepts his dinner invitation in order to learn the whereabouts of his father. The evening is spent with Michael attempting to seduce her and trying to get information out of her. It ends with neither one being any more informed than when it started. Wanting to see her again and to continue to try and solve her mystery Michael uses the lure of his stable to get her to visit Bredon Hall the next day. While she is there, Michael's flamboyant best friend Hamdan al Dubai (Leigh Lawson) arrives with his manservant Fordingbridge to discuss a filly with the horse manager. Much to Michael’s annoyance Hamdan immediately homes in on Casey and begins enacting what is most likely an age old game between them of trying to steal the other’s most recent conquest. After Casey learns that Michael's father is in London she accepts an offer made by Hamdan to go back there with him. This arouses Michael's suspicions a fresh and on a horseback ride while they wait for Hamdan to conclude his business he makes another unsuccessful effort for details
Arriving back in London, Casey is able to find Lord Bredon at his office in Half Moon Square. While visibly shaken by the news of Jessie's death, he denies ever having known her and refuses to accept the letter. Instead of deterring her, Richard's confusing reaction only serves to make her more determined to uncover the mystery. Back at the hotel she finds that Michael has sent her flowers and during a phone call to thank him he asks her out for the afternoon of the following day. The scene then switches to Richard's office at Bredon Enterprises where he is clearly caught up in memories of the past brought on by his earlier meeting with Casey.
The next day Hamdan calls to charm Casey into having lunch with him on his yacht. Michael, upon finding out her plans with Hamden, shows up at lunch uninvited but not unexpected by Fordingbridge who appears to be used to games that Michael and Hamdan play. The talk switches to a discussion of the party going on at Hamdan's house that evening. Hamdan invites her to the event but it's not until she finds out Lord Bredon is going to be there that she accepts. Later that evening as Casey is preparing to go she and Michael quibble over the cost of the dress he has bought her for the party. When she capitulates to him he looks over and happens to see that she's wearing a necklace that reminds him of his family crest. When she claims that it belonged to her mother he persists in trying to talk about it but she laughing blows off the conversation.
At the party Casey and Michael are having a great time but that is soon stopped by a confrontation with his father who accuses her of being a con artist and tells his son about her trip to his office. Michael, who has a deep fear of being taken in by a woman, immediately lays into her. Casey becomes distraught by both men attacking her and runs off. Michael chases after her ultimately cornering her in a garden house where they end up in a passionate embrace. He agrees to hear her side of the story and the pair leave the party. Richard observes them leaving and a firework going off nearby takes him into a flashback. The scene changes to WWII where a young Richard and a woman who is clearly Jessie Cantrell flee to a bomb shelter during a German air strike. In the shelter Richard admits his love for Jessie despite having known her for only a short time. Coming out of the flashback Richard asks Hamdan to dig up information on Casey. Hamdan expresses his discomfort with the situation but this falls on deaf ears.
Michael and Casey arrive at his apartment after her having told him the story about the letter on the way there. The two reexamine the pendant with him verifying that is the family crest. She postulates the theory that her mother and his father knew each other during the war. The scene fades to Richard driving home from the party and having a flashback about when he first met Jessie. It is revealed in the course of the flashback that Jessie was living with a friend of Richard’s named Emily and that she was married to someone named Frank and that Frank appears to have died. The scene switches again back to the present day where Casey and Michael are talking about how Jessie might have met Richard. This leads to Michael seducing a a somewhat reluctant Casey and carrying her off to bed. Later Richard arrives back at Half Moon Square, and it's revealed that the place was where Richard and Jessie used to meet.
The next morning Hamdan sees Michael and Casey in a clinch on Michael's balcony. He's next seen talking with Richard on the phone. Richard asks him to work on Casey while he talks to Michael who is planning to come into the office. Once again Hamden expresses reluctance to involve himself in the situation but Richard hangs up on him. Hamdan then goes to see Casey at her hotel and ends up going with her to track down a woman whose name is in her mother's address book. While riding down the river Hamdan makes his position clear about his friendship with the Bredons, especially Michael, and that he wouldn't allow anyone to harm them. Casey swears that she would never do that. Back the office Richard confronts Michael about not getting rid of Casey and then Michael turns the confrontation on him asking how Casey's mother got the pendant. Richard kicks him out and goes into a flashback where it's revealed that Richard did in fact gave the pendant to Jessie.
At a pub on the river Fordingbridge, who does a bit of sleuthing while getting drinks, reveals that the older lady he and Hamdan see Casey talking to is an old friend of her mother's named Billie Cooper. The scene shifts to Casey talking with Billie who confirms that Jessie was in England during the war. Billie further reveals that she came over as a member of the USO to follow Frank, Casey's father. Billie tells her about a fateful mission in which Frank was believed to have died trying to save Billie's husband. Billie continues the story where she confirms that Richard and Jessie knew one another and that their interest in each other was much to the disappointment of Richard’s old friend, Jessie’s flat mate Emily. A flashback reveals that Jessie got a telegram saying that Frank was still alive complicating her situation with Richard. As the two are talking Hamdan finally calls a PI to investigate Casey.
Later at Michael's apartment Casey brings him up to speed on the situation. Michael has difficulty taking in this new information about his father and Casey expresses discomfort about what she sees as a shifting perspective of her parents. Michael and Casey end up revealing their feelings for one another and Michael asks Casey to marry him. At first she questions whether he really means it given their short acquaintance, and he explains that he feels that he has at last found what he believes to be true love. She accepts his proposal.
Later at Bredon Hall, Michael tries to get Richard to read Jessie's letter. Richard continues to refuse. Michael confronts him with the knowledge that he knows about his relationship with Jessie. Richard, feeling that he can no longer deny it to Michael, confesses to having been in love with her. He also believes that Jessie screwed him over. Michael tells him that he is in love with Casey and plans to marry her. Richard continues to assert that he believes Casey to be a con artist and Michael walks out on him. A flashback reveals that Richard did intend to ask Jessie to marry him but when she didn't show up for their scheduled meeting he found out from Emily that Jessie had disappeared.
Later Richard goes to meet with Hamdan at Bredon Enterprises to find out the results of the investigation on Casey. He not only learns that Casey’s record is clear but that Frank was discovered not to have died around the time that Jessie vanished. This changes his whole perspective on what happened and he contacts Michael to apologize.
Michael leaves Casey alone at his apartment to go to see his father. While she is alone there Casey receives a visit from Michael's mother. She turns out to be the Emily whose flat Jessie shared while she was in England. Emily tells the rest of the story which involves her meeting up with Jessie sometime after she had left London. Jessie was caring for Frank who was now being treated for blindness that he got from the explosion and wasn't aware that Jessie was pregnant with Richard's baby. Emily revealed to Jessie that she had married Richard and agreed to take and raise the baby as her own. The baby turns out to be Michael of course and the revelation prohibits marriage between him and Casey.
Casey flees the flat and runs to Hamden. After crying her heart out in the cabin on his yacht she tells Hamdan that she is leaving and asks him to take her to the airport. Fordingbridge, alarmed by the situation, calls Michael to tell him what was going on, and Michael races to the pier to try and talk to Casey. At first she is reluctant to do so but Hamdan convinces her that she must and she reveals to Michael the story Emily told her.
At Bredon Enterprises Richard confronts Emily about what happened believing that somehow she interfered. A flashback reveals that in her determination to be the mistress of Bredon Hall and Richard's wife she manipulated events so that Richard was led to believe that Jessie had abandoned him. She then screws the knife in further by revealing to him the truth about Michael.
Fordingbridge and Hamden arrive at the hotel to take Casey to the airport. Fordingbridge, who has developed a fondness Casey, has provided Hamden another file on her and his attitude reveals that he believes Hamden's probing has something to do with why Casey is leaving. On the drive, Casey reveals the whole story to Hamdan. As she dozes off in the seat next to him a flummoxed Hamdan remembers the file Fordingbridge gave him and looks through it. Whatever is in the file causes Hamdan mood to change for the positive and the then leans over and whispers something to Fordingbridge. Fordingbridge changes the car’s direction.
Back at Bredon Hall Richard and Michael have gotten together to share the reading of the letter. Hamdan's car pulls up outside and Casey awakens from her nap to find that she's there. She is distressed by this but Hamdan convinces her to come in with him. Once in the room with Michael and his father Hamdan hands Richard the file. Richard reads through it and then goes to sit next to Casey. He apologizes to her for how he behaved then reveals that according to the file Casey is actually not Jessie's and Frank's biological child and that she was adopted thus clearing the way for Casey and Michael's relationship to move forward. As Michael rushes to her side Richard lets her know that as Jessie sent her there to them they are now her family.
The film closes with Richard rereading Jessie's letter then watching Michael and Casey from the window as they embrace.