The speaker walks across a landscape in the course of an afternoon, noticing small things: a leaf that lifts and drifts away, a distant warbling that seems to change meaning as he gets closer, marigolds turned toward a weak sun. Nature feels full of messages, but none can be fully read. Even the music of the afternoon is described as "unbearable," which hints at a beauty that hurts a little.
Then the mood darkens. Night arrives "too soon," and the speaker's sense of dread, "a river thick and black with portent," comes through. The parenthetical image of shades warming their hands against cold stars, then pocketing them "without solace," feels lonely and strange. The ending is quietly deflating. The night turns out not to be special, and the speaker simply reaches a lit porch. The poem seems to suggest that all this heightened attention, and the sense of something about to happen, leads to an ordinary evening and a certain disappointment.