"Anyway. What do you want?" He admits he's been skiving, but after all, the last time they spoke Sigma said his song would be ending soon, and after all who wants that? He locks the TARDIS adorably, with a beeping car key, trying to get a rise out of Sigma, but it's no use. "I locked it, like a car? Like... It's funny. No? Little bit? Blimey, try to make an Ood laugh."
They walk. The Ood city is beautiful in the snow; he nudges Sigma appreciatively but gets scared when he learns it's only been a hundred years since they were freed. "All of this is way too fast. Not just the city, I mean your ability to call me, reaching all the way back to the 21st century. Something's accelerating your species way beyond normal." That something is need. "The Mind of the Ood is troubled. Every night, we have bad dreams."
Sigma takes him down into the caves of the Elders, where an oracle takes the smoke and spins an astrolabe or orrery as the rest of the circle moans. "Returning, returning, returning, it is slowly returning. Through the dark and the fire and the blood, always returning, returning to this world. It is returning, and he is returning, and they are returning. But too late, too late, far too late, he is come..." It's Ood wordplay, but what it means is buffalo. The Last of the Time Lords: He, and they, and you are returning. The Doctor sits with the Elders, to share the Dreaming. To join with them, in their song.
The first thing he sees is the Master, laughing, just as in Wilf's vision. The sound he heard, well in the back, far as drums, when he ruined Adelaide. "He comes to us. Every night. I think all the peoples of the universe dream of him now..." The Doctor swears he's dead, but they're not done. "Join us. Events are taking shape. So many years ago, and yet changing the now. There is a man..." The Doctor steels himself for it this time, but it's Wilf: "So scared." The Doctor freaks out, first for Wilf and then inevitably for Donna. "You should not have delayed, for the lines of convergence are being drawn across the Earth. Even now the king is in his counting house," they say, showing him the Naismiths, whom the Doctor doesn't yet recognize.
"And there is another. The most lonely of all, lost and forgotten." Lucy Saxon shivers in a cell, sobbing. The Ood ask after her, and the Doctor is compassionate in explanation: "It wasn't her fault, she was... The Master, he's a Time Lord, like me. The Master took the name of Saxon. He married a human, a woman called Lucy, and he corrupted her. She stood at his side while he conquered the Earth." He swears that year never happened. He wishes it never had. But Lucy Saxon remembered.