The speaker dreams of someone they clearly miss. The person sits on a chair, glances sideways, and speaks kind words with a warm smile. The speaker is amused to notice the figure looks young and a little plump, though "you never were plumb," and quietly marvels at how much they have changed. The poem never says who this person is or why they are absent, so the reader has to infer a loss or a long separation from the longing in the speaker's voice.
The feeling is tender and happy at first, then wistful. As the images start to fade, the speaker wishes it weren't a dream. The picture shrinks to a thin bright line, then a dot, then black, like a screen switching off. The ending is sudden and quiet: a dove on the window sill flies up in a flurry of wings. It could be the real world intruding on the dream, or a small sign of peace. The mood is soft, nostalgic, and gently sad.