The poem is set in winter, though the knight recalls a more bountiful season as he tells his story to the questioner.
As the poem opens—in what is the present day in the poem—it is silent and the landscape is withered, suggesting the deathlike atmosphere of winter. The speaker asks the knight twice,
O what can ail thee, knight-at-arms?
The speaker says, too, the the knight looks "pale," "haggard," and "woe-begone."
The knight then tells his story. He met a beautiful woman. At this point, in the past, it was spring or summer. He made her a "garland," and she fed him "roots of relish sweet" as well as manna and honey. All seemed well until the woman took him to her grotto and lulled him to sleep. When he awoke, after a horrible dream of seeing "death-pale" warriors, he found himself alone on a "cold" hillside, the woman gone. In the dream, he was told by the other men that the woman was the "Belle Dame sans Merci," or the beautiful lady without mercy, who abandoned him as heartlessly as she had the others.
Variations of the word wither are used repeatedly to describe the landscape. The cold, wintry setting matches the cold, deathlike feelings that hold the knight in their grip. This is an example of the pathetic fallacy, which occurs when the weather or the landscape reflects the emotional state of a character in a work of literature.