Novice Hame: (about the Face of Boe) I can hear him singing sometimes. In my mind. Such ancient songs.
The Doctor: Am I the only visitor?
Novice Hame: The rest of Boe-kind became extinct long ago. He's the only one left. Legend says that the Face of Boe has watched the universe grow old. There's all sorts of superstitions around him. One story says that - just before his death - the Face of Boe will impart his great secret. He will speak those words only to one like himself.