"Bluebeard had given her power to roam the entire chateau, except for one room which was always locked. When he had to leave on a voyage, he gave her all the keys to the household, including the key to the forbidden room. As soon as he was gone, she hastened to the room to see what was inside..."
This illustration is based on Charles Perrault's story of Bluebeard. I imagine the heroine as apprehensive and pale as she approaches her husband's hidden secrets.