(AudioGo)

THIS is the story which established historical ground rules for Doctor Who which are directly challenged by subsequent adventures to the point whereby the show now celebrates the fact that “history can be re-written”.

When the Doctor warns teacher Barbara Wright that “not one line” of known history can be altered, he effectively places himself and his companions in the roles of detached observers, watching over events but doing nothing to alter what subsequently appears in the history books.

Had that remained the situation then much of the drama in the series would have been lost, as part of the fun of later stories is seeing the time travellers interfering in the past with almost reckless abandon, including starting legendary fires in 1st century Rome and 17th century London, saving Queen Victoria from a werewolf, and writing “This is a fake!” on the canvas used for assorted duplicates of the Mona Lisa.

The premise here is simple, yet effective. After arriving in 15th century Mexico, Barbara is mistaken for a reincarnation of the ancient Aztec high priest Yetaxa, and decides to use her newfound influence to bring an end to the culture’s propensity for human sacrifice in a bid to save them from extinction when the Spanish Conquistadors arrive…

In the meantime, the Doctor finds himself unexpectedly engaged when sharing a cup of cocoa, Ian is forced into the military, and Susan transgresses Aztec law by refusing the marry their Perfect Victim, who has been scheduled for sacrifice on the day of the next solar eclipse.

In many ways, this is the archetypal Doctor Who historical, free of alien invaders, fulfilling the series’ original remit to be both educational and entertaining, and offering a thrilling episodic adventure for the main cast.

However, it is also a first-rate example of British television drama, a story which stands up to repeat viewing almost 50 years after it was first screened, and in this format, a novelisation which succeeds in expanding upon the events on screen and building a much more detailed picture of this time-lost world, even though the odd anachronism slips through.

Original series companion William (Ian Chesterton) Russell might be in his late eighties, but he can still spin a ripping yarn. His vocal talents have enjoyed a renaissance as of late, with readings of Who novels and appearances in spin-off audios as Ian, and this continues here with a first-rate reading of John Lucarotti’s novel.