In the TARDIS, which a few hours ago had been bursting with life, the Doctor now found himself alone. The Doctor soon became tired and went to his private quarters. He got ready for bed and fell asleep.
He suddenly found himself in a park on Earth. Sitting on a wooden bench, the Doctor looked up at the sky and a flock of geese caught his attention: a family traveling together from place to place, wherever their whims decide. Always together; there to protect one another, with a leader at the helm to-
The Doctor suddenly realized that he was not alone. Sitting next to him on the bench was an old man with white hair and wearing Edwardian style clothes. His hands rested against a cane. The Doctor recognized him instantly.
"It's you! Or should I say me?" the Tenth Doctor said.
"Oh," replied the First Doctor. "Which one are you?"
The First Doctor studied his future self carefully. "A tad skinny."
"Yeah, but it wears well in travel."
"Good. I hate having to stop and rest every five minutes."
"Yeah, uh, look," said the Tenth Doctor. "I don't mean to be rude; I mean it's brilliant and all that you're here, but how can we be in the same place at the same time without, like, the universe exploding?"
"Simple, my boy. You're asleep."
"Oh," said the Tenth Doctor, his predecessors words dawning on him as the truth. "Yeah, that's right! Brilliant!"
"So tell me, what have I been up to lately?"
"Oh, this and that. Saving Earth from destruction."
"Ah yes, Earth," mused the First Doctor, grabbing his lapels. "It has begun to grow on me. Susan loves it, you know."
"Yes, I know."
"And Barbara has turned out to be a splendid woman. I'm even beginning to warm up to Chesterfield."
"That's what I said."
After a short silence, the First Doctor arose and said, "Follow me." The Tenth Doctor got up from the bench and curiously followed a few steps behind.
They strolled through the park, the First stopping every so often to study a particularly interesting flower or animal.
"Where are we going?" the Tenth finally asked after a while.
"What do you mean?"
"You wanted me to follow you somewhere."
"No," answered the First. "You've misunderstood completely. I wanted to have a look around this place; it's quite extraordinary."
"I hadn't really noticed."
"And that's the problem, my dear boy. You must remember to care because once you stop noticing the world around you, you become unable to enjoy the memories of it later on."
"I've started to no longer see the need for certain memories. I've seen death and destruction, the loss of innocence, the hardening of hearts. Why should I have to remember those?"
"You might as well question the very idea of living!" argued the First Doctor. "You can't enjoy the pleasures of life without experiencing the pain."
"But everything I've ever cared about is now only a memory," replied his tenth self. "They're all either dead or have someone else to care about. And however amazing things were, there are moments that not even a Time Lord can revisit. The memories have just become painful now."
"But there are always new experiences," proposed the First Doctor.
"What's the point? Time is fleeting."
"'And the hearts, though stout and brave, still, like muffled drums, are beating funeral marches to the grave.'"
"No one can live forever. No one should."
"I know that," said the Tenth Doctor. "But having to watch everything around me disappear into nothingness can make me feel a bit lonely at times."
"Nothingness," the First Doctor said. "Listen to the world around you. Does that sound like nothingness?"
The Tenth Doctor closed his eyes and stood in silence as the rhythm of the universe passed through his ears: the flowers swaying in the wind, the bees buzzing around their hive, the children trampling on the grass. The harmony was so intense, so beautiful that a tear formed at the corner of the Doctor's eye. He opened his lids and looked at the man he once was. "Thank you."
"It was nothing, my boy."
The park was starting to fade around the two figures. "It seems you're about to wake up," explained the First Doctor. "But before you do, whenever you feel alone, just remember to listen to the sound of the universe; it will always be there for you." The scene vanished.
The Doctor awoke inside the TARDIS. Refreshed, he walked into the main console room with ready ears.