Lacy and the Doctor are similar, he just doesn't know that yet. They both don't know that yet... Lacania of Gallifrey, the Time Lord he loved on Gallifrey. She waited a Thousand years for him, but he Never came back. So he mourned her and her planets death for so long. But what would happen if she escaped? What would happen if they were to meet again? And what if... What if Lacania... Was actually Lacy?
7 parts