The Doctor Falls the episode, the Doctor (Peter Capaldi) must save himself and the remaining human population of a gigantic colony ship from Mondas, while also dealing with two different incarnations of the Master (Michelle Gomez and John Simm) at once. The episode features a cameo from the First Doctor, now portrayed by David Bradley. He had previously played William Hartnell, the original First Doctor actor, in the 2013 "Doctor Who" docudrama "An Adventure in Space and Time". Aboard the colony ship reversing from the event horizon of a black hole, the Doctor finds Bill has been converted into a Cyberman. The Master
An Adventure in Space and Time was in the Season 21 serial "Frontios"; Mark Eden appeared as the title character in the Season 1 serial "Marco Polo"; Nicholas Briggs, who has voiced the Daleks since the series was revived in 2005, portrayed his own predecessor; and Brian Cox voiced the Elder Ood in "The End of Time". Jean Marsh and Anneke Wills, who both played companions to Hartnell's First Doctor also appeared during Verity Lambert's leaving party scene. The drama was watched by 2.71 million viewers in the UK. Rotten Tomatoes gave it a 95% approval rating based on 22 reviews, and an average score of