This is Mrs. Mallard. She is married to Brently Mallard and has heart troubles. Also, her husband was believed to have been involved in a railroad accident that left him dead.
After her sister broke the news to Mrs. Mallard that her husband was leading the list of "killed" she isolated herself in her room, until she started thinking about her future. She then started to whisper to herself.
Free, free, free!
She then reached a state of "clear and exalted perception. This made her realize that she could finally live for herself as she pleased.
She felt like a "goddess of victory" as she traveled down the steps with her sister, Josephine. As the reached the bottom, however, she found that someone with a key was opening the door.
When the door opened, she saw that it was none other than her husband. Apparently, he had been far away from the accident and hadn't known there was one. Mrs. Mallard, who had just attained freedom, literally died.