The prequel to The Doctor, the Widow and the Wardrobewas the first prequel produced by the BBC for the seventh series of Doctor Who. It was the first Christmas themed prequel to be released.
The Eleventh Doctor has his hand on a button that, when released, will blow up a ship that's about to destroy the Earth. He calls Amy Pond on the TARDIS phone to ask her to rescue him, but realises she can't fly the TARDIS, he doesn't have the co-ordinates to give her and she left the TARDISlong ago. The Doctor admits he just wanted to chat, says "Merry Christmas, Amelia", and releases the button. The ship explodes.