After way too long a wait, Doctor Who finally returns on New Year's Day for its twelfth season premiere with a James Bond-inspired two-parter called "Spyfall." This will feature Stephen Fry as the head of MI6 and show Whittaker's Doctor and her companions investigating a sinister alien threat to Britain's secret agents. What we've seen so far indicates that the series is returning in style, too, but what else could the future hold for the thirteenth Doctor?