The poem begins with a speaker addressing a shade (or ghost), describing what might happen if the shade revisited the town where he had lived during his life. The shade may have come to see the statue of himself in town, or to breathe the sea air later in the day when birds outnumber people and humble buildings look momentarily grand. If this is the case, the speaker suggests, the shade should enjoy these things and then leave. Otherwise, the people of the town will go back to their "old tricks," causing trouble for the shade.
The speaker explains that the shade was devoted to serving the people. This reminds the speaker of another, similarly generous man. If the townspeople had allowed it, this generous person would have filled future generations' lives with wisdom and happiness. Unfortunately, he was sent away, slandered, and disgraced by the townspeople. One specific enemy of the shade had also said terrible things about this other generous man and turned the people against him.
The speaker instructs the shade to leave and to cover himself with the "Glasnevin coverlet"—in other words, to retire back to the burial ground. The time to return, breathe the salt air, and listen to the people of the town hasn't arrived yet, and would only fill the shade with more of the sorrow he experienced undeservingly in life. He will be safer in his grave.
