Dark Gallifrey: The Decayed Master Part 3 (6.3)

With the Master bearing down, Naava flees through a skiproad to the plague-infected streets of medieval York. She's seeking her old friend Calix, the greatest of the chronosurgeons, to warn him of the nightmare that pursues her.

But something else is emerging from the skiproads, something twisted and deadly, tearing chunks out of the panicked city. Naava has only one hope to set things right and escape the Master's clutches, and he's hundreds of years in the future, listening out for ghosts of the ancient city.