It opened by explaining how, in the mid seventies, Doctor Who was at its peak. However, change was to come when Elisabeth Sladen decided to leave. Tom Baker approached Philip Hinchcliffe and told him he wouldn't need a new assistant, believing he could carry the show on his own. Hinchcliffe denied his request, but told him that there would be a story with the Doctor on his own: The Deadly Assassin.
Hinchcliffe asked Robert Holmes to write a story, basing it on The Manchurian Candidate. Holmes came back with the suggestion of an alternate reality, that became the Matrix. David Maloney explained how they filmed three version of some Panopticon scenes that were then merged together so that the extras were trebled. Roger Murray-Leach recounted how he created the Panopticon and the Fourth Doctor's cell. He based the Time Lord symbol on the Book of Kells as he thought the Celtic background was rather unique.
Murray-Leach then described how he had written a note in Gallifreyan that was entirely "gobbledegook". This was accidentally given to George Pravda who then had no idea how to perform his scene. For the stories enemy, Holmes wanted to re-introduce the Master. Hinchcliffe allow this on the condition that he was completely different from Roger Delgado's incarnation. Peter Pratt was chosen for the role because of his voice. Hinchciffe was initially worried about how scary this new Master looked, but this was eventually seen as a necessary factor.
The casting of Bernard Horsfall was examined and Hinchcliffe commented that it was good choice seeing as he could convincingly portray the various characters in the Matrix. The documentary then examined how the story had favourable ratings, but poor reviews. Jan Vincent-Rudzki - President of The Doctor Who Appreciation Society in 1976 - commented on how it didn't inform the viewer as to who the Time Lords actually were. However though the Time Lords were nothing like those seen previously and were essentially humans, He did, however, comment that the plot itself was good.
Following this, Mary Whitehouse's criticism of the episode was examined. She took particular dislike to the cliffhanger in which it appears the Doctor has drowned. Hinchcliffe though the scene was fine, but Maloney, in retrospect, thought it may have been a step too far. This scene was later cut when the story was repeated, with the cliffhanger being Goth's final line.