Doctor Who: A Christmas Carol - Synopsis (UPDATED)

The BBC Press Office have released the synopsis for this year's Doctor Who Christmas special, A Christmas Carol:

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?

The episode will broadcast on BBC One and BBC One HD, a time is to be confirmed.

UPDATE: The BBC have now confirmed that the festive episode will broadcast at the time of 6:00pm.