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 Chase (Doctor Who) the last appearance of Russell and Hill as companions Ian and Barbara and the introduction of Peter Purves as new companion Steven Taylor. In the TARDIS, the Doctor, Ian, Barbara, and Vicki are huddling around the Time-Space Visualiser, a television-like souvenir from their recent adventure at the Space Museum, which can pick up on any past event in the whole of time and space. The TARDIS then lands, and the Doctor confirms conditions are hospitable. Ian and Vicki leave to explore the desert wilderness. They find an ancient trap door in the sand. Inside, they are trapped — and become