In the series 10 finale "The Doctor Falls", David Bradley appeared as the First Doctor, confronting his twelfth incarnation as the latter resists his oncoming regeneration. This scene was followed up in the 2017 Christmas special, "Twice Upon a Time". Bradley had previously portrayed William Hartnell in "An Adventure in Space and Time", a 2013 docudrama depicting the creation of "Doctor Who". He reprised the role of the First Doctor for a series of audio stories released by Big Finish, titled "", starting in January 2018; in "The Destination Wars", the Doctor encounters an early incarnation of the Master who has created a state of war on the planet Destination to provoke a level of technological development that will allow him to repair his damaged TARDIS, and in "The Great White Hurricane" the TARDIS crew are separated when they arrive in New York just before the Great Blizzard of 1888. "The Invention of Death" brings the crew to a planet of giant single-celled organisms where they inadvertently introduce the concept of procreation and death to the culture, and "The Barbarian and the Samurai" traps the crew in political conflict in mid-nineteenth-century Japan. "The Phoenicians" sees the TARDIS arrive in ancient Tyre and become caught up in the political strife of the time, and "Tick-Tock World" sees the TARDIS crash-land on a planet caught in a complex temporal anomaly, only escaping with the aid of a future version of Susan from a timeline where she remained trapped on that planet for centuries, with the future Susan's actions erasing the TARDIS's original arrival on the planet. "Return to Skaro" has the Doctor's latest attempt to take Ian and Barbara back to Earth bringing them to Skaro years after the defeat of the Daleks in time to deal with the Daleks' return after they have subverted a recent Thal project, and in "Last of the Romanovs", the TARDIS crew meet the Tsar and his family the night before their execution, with the Doctor expressing his regrets that he cannot do anything to change the Tsar's fate (all-but-explicitly referring to their deaths as a fixed point in time).