The Doctor's heart-breaking farewell to Amy and Rory.
Christmas Eve 1892. When a chilling menace threatens Earth, an unorthodox governess, Clara, calls on the Doctor for help. But the Doctor is in mourning. Will the Doctor really abandon humankind?
The search for Clara brings the Doctor to London, where something deadly is in the Wi-Fi.
The Doctor takes Clara to the Festival of Offerings, but the Old God is waking...
On a Russian submarine, a frozen alien warrior is waking up, just as the TARDIS arrives.