[1] The story deals with two telepaths named Robb and Lyanna ("Lya" for short), who visit the planet Shkea by an invitation of the planetary administrator, who is disconcerted by the culture of the native alien population, the Shkeen, and how it affects humans.

When he wakes up, one of the locals tells him that after he tried to read the people in the cave, he lost control and tried to walk into the Greeshka, and the rest of them had to render him unconscious to get him out.

Later, Lya communicates with him in his sleep, telling him that she went to a cave and allowed herself to be consumed by the Greeshka, which she says is a link to an afterlife of sorts where the minds of every person who has been absorbed by it live and share love without any loneliness.

At the end, afraid that if he stays longer in Shkea he will succumb to the attraction of the Greeshka, Robb decides to return to his homeworld, hoping to find a means of transcendence and to overcome loneliness that is not Shkeen, but purely human.

[2][3][4][5] A Song for Lya is set in the same fictional "Thousand Worlds" universe as several of Martin's other works, including Dying of the Light, Sandkings, Nightflyers, "The Way of Cross and Dragon" and the stories collected in Tuf Voyaging.