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
Doctor Who in Australia were still only around twelve months behind their original BBC transmission dates. In October 1966 the first episode of "The Space Museum" marked the first time the ABC stripped Doctor Who in the 6:30 Monday–Thursday timeslot. With only occasional changes or minor variations to days and times, the ABC continued to strip "Doctor Who" in a weekday early-evening timeslot for much of the next twenty-six years. Later in 1966 the ABC also started showing repeats of chunks of the most recent first-run stories in the same stripped prime-time slot. (Repeats not only remained commonplace, but their regularity also went on