Gwenda, a wealthy young woman, had bought a house on the English coast. However, she began experiencing disturbing visions that made her anxious and confused.
Miss Marple was asked to investigate Gwenda's situation and help her find out what was causing these visions. After some investigation, Miss Marple discovered that Gwenda had lived in the house as a child and witnessed a murder of a beautiful woman named "Helen." The visions were actually flashes of memory from that time.
As a result, Gwenda realized that she had been haunted by the events of her childhood, which had caused her to experience these disturbing visions. She decided to confront her past and move on with her life.