Christmas is a time for many things. For family and old acquaintances. For giving, for receiving, for feasts and celebration. For huddling round the warmth of the fire, sheltered from the dark and the cold outside.
And the monsters.
It's also the busiest time of year for the mysterious Doctor, whether he's caught-up in the violence of ancient Rome, taking Leonardo da Vinci on a day-trip to the stars, or popping in on the very first Christmas on the moon.