Lucky is not her real name, but Greg gave her that nickname because he said that she was his "good-luck piece", and that if he lost her, he would lose his luck.
Miss Marple is easily able to fit Lucky to a village parallel, Marleen, at the Three Crowns.
According to Miss Prescott, Lucky was a cousin or relation of Greg's first wife, Gail. Lucky, whom Miss Prescott thought was called Miss Greatorex at the time, had come out to the caribbean to join Greg and Gail. She had done some work with Greg, and also looked after Gail. People had talked because Greg and Lucky got on so well together.
Lucky was said to have seemed very devoted to Gail, but when Gail died suddenly, Greg married Lucky very quickly afterward. This also caused people to talk. Miss Prescott believed that they had gotten married only a month after Gail had died.
It is revealed that Lucky had an affair with Colonel Edward Hillingdon. However, she did not want to divorce Greg, as he was very rich, having inherited a lot of money from Gail.
It is also revealed that Lucky had plotted to kill Gail, and tricked Colonel Hillingdon into helping her, by getting him to copy out a prescription and get some drugs from the chemist. She told him that Gail was suffering, and had begged her to get something would end it all. She also told Colonel Hillingdon that because he was the one who wrote out the prescription and got the drugs, that he was in it together with her. Even when he stopped caring for her, she continuned to use this to make him feel tied to her.
Towards the end of the novel, a body is found in the creek, which is initially thought to be Molly. However, Miss Marple realises that it is Lucky when she notices that the hair is dark at the roots, because it was dyed blonde. This makes Lucky the third murder victim.
In the 1983 Warner Bros adaptation of A Caribbean Mystery, Lucky is portrayed by Cassie Yates.
In the BBC 1989 adaptation of A Caribbean Mystery, Lucky is portrayed by Sue Lloyd.
In the 2013 ITV adaptation of A Caribbean Mystery, Lucky is portrayed by MyAnna Buring. In this adaptation, she had a first husband, one Parker De Witt III. Evelyn Hillingdon accused her of killing Parker by persuading Edward Hillingdon to get the poison for her. She claims Parker was already dying and sick and a few months didn't make any difference. Lucky subsequently married Greg Dyson. By the time of the events in the show, they no longer loved each other but could not divorce because they shared the secret of Parker's death. Although Greg insisted he had nothing to do with it, Lucky reminded him that since he married her, he would always be a natural suspect. In this adaptation, also, Lucky was a cocaine addict, and obtained some of it from Victoria Johnson. Miss Marple surmised that what she had done to Parker had driven her to depression. Lucky died by being pushed off a cliff. Tim Kendal had mistaken her for Molly as she was standing at Molly's favourite spot and wearing a shawl like Molly's which she had admired earlier.
In Albert Major parlait trop, the Les Petits Meurtres d'Agatha Christie adaptation of the novel, the parallel character is Lucette Vidal, the wife of Grégoire Vidal, the head of the Hôpital Saint Paul where the events are set.