Parts: 1 (60-minute)
Writers: Steven Moffat
Airdate: 25 December 2014
Production Code: n/a

Doctor: twelfth
Companions: Clara

Creature Feature: Kantrofarri

Story: In the middle of the night, on Christmas Eve, Clara is awoken by strange sounds on her rooftop. Upon investigating, she finds that the least plausible explanation is in fact the correct one: a sleigh has crashed on the house, stranding Santa and two of his elves.

But Clara has very little time to process this bizarre new twist of fate before the Doctor unexpectedly shows up, confronting Father Christmas - and ignoring his words of warning - before whisking Clara off to an arctic research station, where several crewmembers have been attacked by predatory alien creatures. Immobile in their sickbeds, the "sleepers" are totally inert unless someone looks at them, or thinks about them... and then they come to life, and attack...