Louise Mallard's first reaction to the news of her husband's death is a "storm of grief" that spends itself quickly; she then retreats to her bedroom, alone. We learn, from the narrator's description of this response, that Louise had reacted unusually: "She did not hear the story as many women have heard the same, with a paralyzed inability to accept its significance." In other words, Louise doesn't react the way most other women have or would have.
As she sits, alone in her room, the narrator describes all the signs of "new spring life" that Louise sees outside of the window. This is another clue to Louise's unusual reaction: she notices only the pleasant things. She sees the "tops of trees that were all aquiver" and the smells "delicious breath of rain . . . in the air." She hears someone singing far away as well as the "countless sparrows . . . twittering in the eaves," and she sees that there are "patches of blue sky" showing through the clouds. It is as though what is happening outside, the signs of the rebirth of nature in spring, is echoing what is happening to Louise inside: she is realizing that she has been reborn, so to speak, as a free woman. The only words she says for quite a while are "'free, free, free!'" Rather than feeling any stress or tension, "Her pulses beat fast, and the coursing blood warmed and relaxed every inch of her body."
Louise's last words are to her sister, assuring Josephine that she is not making herself sick inside the room alone. Finally, she descends the stairs "like a goddess of Victory," reveling in her new freedom. That is, until she sees her husband, very much alive, walk through the door, effectively closing the door on the freedom she dreamed she had.