This is Samweis Gamgee, sitting at the stairs of the dark Orc-tower. He's weeping and desperate, because his best friend died, as he thinks, and he himself has to destroy the One Ring on his own. That‘s so much demanded from such a little Hobbit, who begins to understand, that this journey will surely be his death. And so he starts singing. He sings a little song from the shire, his beloved home land and wishes, he was never went away from there.