premise: The Tenth Doctor travels alone in The End of Time.
hypothesis: Tenth Doctor . In the programme 's narrative , the Doctor is a centuries-old Time Lord alien from the planet Gallifrey who travels in time in his TARDIS , frequently with companions . He eventually parts ways with them all by the end of the 2008 series finale , `` Journey 's End '' , after which he attempts to travel alone for the duration of the 2008 -- 2010 specials before being accompanied by Donna Noble 's grandfather Wilfred Mott on his final adventure in The End of Time . The End of Time (Doctor Who) . The story features the Tenth Doctor ( Tennant ) , who has been running from a prophecy of his impending demise , as he is drawn into a scheme by his old nemesis , the Master ( Simm ) .