Kate Chopin's "The Story of an Hour" seems to be about a woman with a bad heart who dies when she finds out her husband is still alive—after he has been reported killed. This is not the case at all.
One of the things that makes this story so masterfully written is that Chopin is able to stun the reader in a few short pages: it startles and then creates questions for debate.
Louise Mallard hears that her husband has been killed in a train wreck. She is told in the kindest way possible and breaks down immediately, crying in her sister's arms. However, it is not until she retires to her room, with time to think, that she begins to see the world in a completely different way, one that she fights off at first, defending her psyche against ideas that she initially rejects.
Note that it in this Victorian society, women belonged to their husbands: they were considered weak, helpless individuals that could not survive without a father or husband. Louise is like most women of her time: she has never considered a life different than the one she was born to. She has never longed for individuality—in fact, the story suggests that she has never considered that such a thing exists.
Before anything else, we are told about Louise's health:
Knowing that Mrs. Mallard was afflicted with a heart trouble, great care was taken to break to her as gently as possible the news of her husband's death.
This sets the mood: Mrs. Mallard has serious health issues. She is nearly an invalid. The mood is how the reader is made to feel. However, the tone—how the author feels about his (or her) subject—will not become apparent until her epiphany.
Louise goes to her room, looking out the window and resting. She is a young woman whose face has "lines [that] bespoke repression and even a certain strength." An epiphany comes to her even though she fights to keep it away:
She was beginning to recognize this thing that was approaching to possess her, and she was striving to beat it back with her will...
Dutifully, this woman tries to maintain her social place...but the truth comes to her even as it terrorizes her, for a time:
...free, free, free!
After she deals with her husband's death, she sees a line of years of freedom ahead that she would never have had if Brently had lived...
...she would live for herself. There would be no powerful will bending hers in that blind persistence with which men and women believe they have a right to impose a private will upon a fellow creature. A kind intention or a cruel intention made the act seem no less a crime...
She is exultant: "Free! Body and soul free!"
Coming to terms with this realization, she finally agrees to leave her room at her sister's importunities. Coming down the stairs, she witnesses the door opening on her husband's disheveled form: there had been a mistake. When the doctors arrive...
...they said she had died of heart disease—of joy that kills.
Here, then, is the tone. Louise died because she could not face a life without her newfound freedom. Her patriarchal society would say she died because she was overjoyed to see Brently still alive. Chopin scandalized society—her message was clearly that women were entitled to freedom, the same as any man. Louise does not die from joy. Unable to live without her newfound freedom, she dies from a broken heart!