EPISODE: Children In Need Special 2007
AIR DATE: November 16, 2007
ALIENS/ MONSTERS: None
OTHER CHARACTERS: None but mentioned, Teagan, Nyssa, and The Master
This story follows on from Last of the Time Lords: the Tenth Doctor has just said goodbye to Martha, and is attempting to take off when the TARDIS suddenly goes haywire.
Suddenly, someone else is in the TARDIS: the Fifth Doctor. The Tenth Doctor realises straight away this is his past incarnation and is soon reminiscing about his adventures as the Fifth Doctor, much to the latter's confusion. The Fifth Doctor decides that the strange skinny bloke in his TARDIS is an obsessive fan of his--possibly affiliated with LINDA--and the Tenth, to his own bewilderment, can't convince his past self otherwise.
Meanwhile, the collision of the TARDIS with its past (or future) self threatens to tear a hole in the universe; one the exact size of Belgium--which, as the Fifth Doctor remarks, is a rather undramatic description. The Fifth Doctor despairs of finding a solution in time, but the Tenth purposefully--if maniacally--manipulates the TARDIS controls and averts the disaster.
Stunned by the unexpected solution, the Fifth Doctor realizes that the other man is in fact his future self. The Tenth Doctor bids a warm farewell to his past self; and, with a final warning to his future self to restore the TARDIS shields, the Fifth Doctor rejoins his own timeline.
But suddenly, it's too late to put up the shields... the Titanic has plowed through the wall of the TARDIS.