The final part of my reconstruction of this mostly missing Who serial, made using telesnaps, publicity stills and the existing soundtrack (narrated by Frazer Hines).
Keep watching after the end credits for the trailer for the next story, The Ice Warriors, which followed the original transmission of this episode.
Note: due to the age of the programme and the off-air nature of the source material, the sound quality varies.
Previously broadcast on YouTube as "Serial NN - Episode 6.3"
The complete soundtrack of this serial (though curiously not the trailer!) is available on CD from BBC Audiobooks.