Fans noticed a pattern between 15th Doctor's companions mirroring the early seasons of New Who. Similarities in character arcs raise questions about a potential repeating storyline pattern.

When Joy was taken to the Time Hotel, the Fifteenth Doctor occupied her room for a year and became ... When the Doctor bid ...

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.