In Tennyson's “Tithonus,” the speaker has received the gift of immortality from the goddess Aurora but not the gift of immortal youth. Therefore, he has grown old and is like a “white-hair'd shadow roaming like a dream” in the mist. He is miserable and regrets that he has ever asked for (much less received) such a gift. It is now a curse.

The speaker looks around him and sees all kinds of evidence of the natural cycle of life and death, a cycle from which he is now excluded. He sees how “the woods decay and fall.” They once were strong and beautiful, but then they follow the way of all things and sink into the ground. The vapors fade away. The swan dies after many summers. Even human beings come and work the earth and then lie beneath that earth in their graves. The clouds drift apart. The days pass. The seasons come and go.

Yet the speaker remains. He cannot die. He cannot join the “happy men that have the power to die.” He begs Aurora to release him, to allow him to return to the earth that he is, to let him rest in his grave. His human nature cannot mix any longer with Aurora's divinity. His immortality has become a prison, and he wants only to rest in peace.