With almost everyone on Earth now recast in his image, The Master controls the Earth. He's shocked however when he realises one person hasn't changed; Donna Noble. The Doctor soon understands what the pounding in the Master's head is; it's the Time Lords, who are trying to return and re-establish Gallifrey. If they succeed, it'll mean the Last Great Time War will re-start, and all the horrors which came with it. In order to stop Rasillon's mad plan, the Doctor must make a choice. Finally, the Ood's prophecy for the Doctor becomes true, and he takes the TARDIS on a trip, to see friends for one last time, before he's to regenerate.