premise: The Tenth Doctor recruits Wilfred Mott to assist him throughout The End of Time.
hypothesis: Tenth Doctor . 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 .