Write a suspenseful short story in third-person limited point of view about a 30-year-old woman named Sarah who discovers a locked secret door in the attic of her newly purchased Victorian-style house. The story should include vivid description of the house and its surroundings, as well as subtle clues scattered throughout that hint at the dark secrets hidden behind the door. Sarah's curiosity and determination to uncover the truth should drive the plot, leading her to uncover a sinister family secret that puts her in grave danger. The story should end with a shocking twist that leaves the reader reeling.
This prompt doesn't seem malicious.