The story opens in black and white, with a scene featuring the Second Doctor and Jamie, which then gradually transitions to colour. This is a homage to The Second Doctor's era, which was shot in monochromatic format.
The last appearances of The Second Doctor and Jamie.
The Second Doctor's claim that he is working on behalf of the Time Lords despite being a renegade is explained by some media and fans by placing this adventure during a supposed period after the Second Doctor's trial, but before his forced regeneration into the Third Doctor and his exile to Earth. This "lost season", where the Second Doctor supposedly worked as a covert agent for the Time Lords, was invented to explain the continuity issue of the Second Doctor knowing the fates of Jamie and Zoe in "The Five Doctors" even though he appeared to regenerate into the Third Doctor immediately after witnessing what happened to them. Some BBC print media has included stories that take place during this supposed period. Of course, regardless of these attempts to rationalise the issue, it remains a gaping plot hole.
At three 45 minute episodes, this was the longest serial to be transmitted during the 1980s and made it similar in length to the six-parters which had been common in the 1970s.
The location shoot in Seville kicked off production. When the wigs constructed for the guest characters such as Chessene and Dastari failed to arrive on time, the actors had to be fitted for new wigs in Seville. These Spanish wigs were subsequently used for the studio shoot in England in order to keep continuity.