Amy and Rory are trapped on a crashing space liner, and the only way The Doctor can rescue them is to save the soul of a lonely old miser, in a festive edition of the time-travelling adventure, written by Steven Moffat.
But is Kazran Sardick, the richest man in Sardicktown, beyond redemption? And what is lurking in the fogs of Christmas Eve?
Amy Pond is played by Karen Gillan, Rory Williams by Arthur Darvill, The Doctor by Matt Smith and Kazran Sardick by Michael Gambon. (Opera singer Katherine Jenkins makes her first acting appearance).
A slight touch of deja vue here, the 2007 Christmas special, Voyage of the Damned, featured the 10th Doctor (David Tennant) dealing with a space liner version of The Titanic and the acting debut of singer Kylie Minogue.