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
The Doctor (Doctor Who) Within the fictional narrative, the Doctor is a Time Lord from the planet Gallifrey who travels through time and space in a dimensionally transcendental – "bigger on the inside" – time machine: the TARDIS (Time And Relative Dimension(s) In Space) which takes the exterior form of a 1963 police telephone call box, and retains the appearance throughout the programme. The Time Lords have dedicated themselves to overseeing all of time and space without interference. The Doctor chose to leave home by stealing an obsolete TARDIS model as revealed in the 1969 serial "The War Games" and depicted in the 2013