Goodbye
The original sin of a timelord is to let nothing end.
They have done Jim the Fish. They have seen the stars from the surfaces of a thousand planets. They have filled a blue book with adventures so wonderful they could overfill the belly of a vengeful god and make him explode with the beauty of them.
But humans are not the only ones who die, and they are not alone in their ability to sacrifice.
He has loved her for as long as a plastic centurion loved a red-headed princess. But everything ends, even the best things. He says goodbye.