The holidays should be a time for peace on earth, but David Tennant's Doctor Who doesn't get to rest in this special that takes him to Christmas Eve, 1851. With the help of another Doctor -- who may be a future incarnation of himself -- the Doctor must battle a CyberKing, CyberMen, and Cybershades who are wreaking havoc on the streets of Victorian-era London. As if that weren't enough, it may take two Doctors to fight a woman who is in league with the Cybermen.