Series 3 (2007)
Episode title: Last of the Time-LordsFeaturing: Tenth Doctor
Companions: Martha Jones, Captain Jack Harkness
First shown: 30th June 2007
Related articles: The Master, Toclafane
Guide: A year after Sound of Drums, the Doctor is held prisoner to the Master, who has conquered the Earth, enslaved its population and made the Doctor age, not able to fight. It was up to Martha Jones to save the universe by carrying out Doctor’s plans.
Martha had travelled the Earth, talking to people, getting them to do one thing. When she arrives back in England, the Master finds her, and captures her, where he has aged the Doctor so that he's small, and lives in a cage on the Valiant.
Martha reveals the plan to the Master, and all at once, everyone, everywhere on the entire planet, chants the same word. "Doctor." As the word is chanted, the Doctor gains strength, and is able to break free of his cage, and regenerate to his young self.
He defeats the Master, but then the Master is shot by his wife, Lucy Saxon, and refuses to regenerate. The Master dies, having beated the Doctor who wanted him to regenerate, and the Doctor cremates him, but someone picks up his ring.
The episode ends with Martha saying good bye to the Doctor, Jack going back to Torchwood, and the Titanic crashing through the walls of the TARDIS, ready for the Christmas special.
This is the third and final episode of a three part story. Read the first part here and the second part here.