Doctor Who: So Vile a Sin

"If you step into history," said the Doctor, "I won't be able to protect you.""This isn't history," said Roz. "This is family."The Earth Empire — the Imperium Humanum, upon which a thousand suns never set — is dying.The Great Houses of the Empire manoeuvre and scheme for advantage; alliances are made; and knives flash in the shadows. Out among the moons of Jupiter, another battle is just beginning, as an ancient brotherhood seeks limitless power and long-overdue revenge.The Doctor returns to the thirtieth century, searching for the source of a terrifying weapon. He fears a nightmare from his own past may be about to destroy the future. Nothing must be allowed to get in his way.But the Doctor has reckoned without the power of history — which has its own plans for the wayward daughter of the House of Forrester.