The speaker goes out walking, back and forth, and eventually comes upon the dead. Whether these are actual ghosts, memories, or a feeling of being surrounded by loss is left open. Either way, the encounter happens in a darkening world: night arrives "too sudden," like falling into "an old hole," a image that suggests both abruptness and something ancient and bottomless.
The speaker asks, "What news of death?", as if the dead might report back from where they are. But they "hear nothing at all." The last lines are the strangest and most striking: they believe "a house on fire / is home to music." It's a chilling picture of people who cannot sense the danger or destruction around them, mistaking catastrophe for song.
The mood is eerie, quiet, and unsettled. The speaker seems curious but also isolated, reaching out and getting no answer. The title, "Dead letter," fits: a message sent that never arrives, or never gets a reply.