Last of the Time Lords

As the end of time draws nearer, "it" returns, "he" knocks four times, and the song ends. Gallifrey is sent back into the Time War, Wilf Mott lives to see another day - and the Doctor dies. And the Last of the Time Lords is left with a key, a piece of paper, silence in his head, and a life with no reason to live. Or the one where the Doctor dies and the Master is left all alone.