Part II of this narrative poem begins with the explanation of why the Lady of Shalott is forbidden from looking at anything outside her window:
No time hath she to sport and play:
A charmed web she weaves alway.
A curse is on her, if she stay
Her weaving, either night or day,
To look down to Camelot.
She knows not what the curse may be;
Therefore she weaveth steadily,
Therefore no other care hath she,
She is under the spell of a curse, and she must spend all her days weaving, forbidden from looking at Camelot via any means except through the mirror which bears its reflection. She is content in her role, and she steadily weaves her way through each day. She really doesn't care about anything down in Camelot, anyway—until the day everything changes. The Lady of Shalott catches a captivating glimpse of Sir Lancelot, and she is compelled to turn away from her mirror and glance down on him directly:
She left the web, she left the loom
She made three paces thro' the room
She saw the water-flower bloom,
She saw the helmet and the plume,
She look'd down to Camelot.
The mirror cracks, sealing her fate for breaking the conditions of the curse. She leaves her room, goes down to the water, inscribes her name on a boat, and gets in. The wind blows her toward Camelot as she sings a song of death. The Lady of Shalott's eyes darken as she turns her face toward "tower'd Camelot," and she dies.