The Aztecs, the latest Doctor Who Special Edition released to DVD by the BBC originally aired towards the end of the show's first series. The serial consists of four half-hour episodes, which aired in May and June of 1964. It is now available on a two-disc set, complete with a wealth of extras.
As The Aztecs opens, the TARDIS lands in a tomb in 15th century Mexico. Upon emerging from said tomb, Barbara (Jacqueline Hill) is mistakenly hailed as an incarnation of an ancient high priestess. Considering she knows quite a bit about this period of human history, she decides it might be best to end the Aztec's practice of human sacrifice here and now, which, in her estimation, could spare them from their eventual extinction at the hands of Spanish conquerors.
At stake in The Aztecs, are the consequences of changing of history. If presented with the opportunity, should anyone alter the present, even if it is possible to rending the world a better place? Or is it preferable to let events run their course, considering that every bad thing still contributes into civilization as it evolves.
If you're satisfied with the present, why risk messing it up by screwing with the past? What unintended consequences could the wreak havoc with the world? Is it even possible to change events, or are certain paths predestined?
These are questions wrestled with since the idea of time travel was first explored, and certainly since the beginnings of Doctor Who nearly five decades ago. There aren't easy or certain answers, and they are still debated today.
Doctor Who does itself a service by addressing them so early on in the show's history, and in a way that viewers would find relatable, as Barbara's intentions are noble. It's intelligent storytelling, and an excellent example of what Doctor Who has to offer the genre.
The Doctor (William Hartnell) is shocked and appalled that Barbara would even consider mucking up events. His mindset and values are not well known, especially at this point in the show's run, but clearly changing history goes against his grain. This makes for some tension between the Doctor and his companion.
The Aztecs is an exciting adventure, with lots of subterfuge and danger. Ian (William Russell) is tasked with battling to the death; there is poison and betrayal. It makes for a great and entertaining batch of episodes, even while raising some important moral issues.