Orbiting a quiet backwater planet, the massed forces of the universe's deadliest species gather, drawn to a mysterious message that echoes out to the stars. And amongst them, The Doctor. Rescuing Clara from a family Christmas dinner, the Time Lord and his best friend must learn what this enigmatic signal means for his own fate and that of the universe.

Originally broadcast as the Doctor Who Christmas Special in Great Britain and the United States on BBC One and BBC America, respectively, in 2013. Special features: Behind the Lens; Tales from the TARDIS; Farewell to Matt Smith.