The speaker looks up at the Moon and thinks of someone they have lost. The poem opens and closes with nearly the same lines, but one word changes everything. First the Moon is "bright & beautiful, just like you," a line full of admiration. By the end it is "so far away from me, just like you." The comparison stays the same, yet the feeling turns from awe to distance and ache.
In the middle, the speaker calls the Moon "our silver Sister," as if it were a shared companion that watched the relationship fade. The phrase "the last days of our dream" suggests something hopeful that slipped away, and the Moon could do nothing but look on.
The mood is quiet, wistful and a little sad. The short lines and simple wording make it feel like a private thought spoken at night, with no anger in it, only longing for someone who is still lovely but can no longer be reached.