The story begins when Emily Arundell, a wealthy but elderly woman, dies in her home in a rural English village. Initially, it appears to be a tragic accident—she fell down the stairs at her house. However, her death is suspicious because she had received a warning months earlier, suggesting that someone was trying to harm her.

Before her death, Emily had written a letter to her niece, Miss Violet Marsh, mentioning her concern about a possible murder attempt and asking for help. However, before Miss Marsh could act, Emily passed away.