Episode One: (This is the serial with which they stopped giving individual episode titles.)
As the TARDIS materializes, the Doctor seems particularly smug that he knows they’ve arrived in some future time. As he leaves to investigate the surroundings, he’s observed by the titular “savages” but actually encounters the “Elders,” representatives of an advanced civilization. Interestingly, they seem to know him as “The Traveler from Beyond Time,” have followed his exploits, and expected his arrival.
Meanwhile, Steven and Dodo have gone off on their own and have encountered the savages. They eventually make their way to the city, however, where the Doctor has become suspicious of the Elders. They have perfected some sort of energy transfer device which steals the energy from one of the indigenous higher life forms on the planet. In case you can’t figure out where this is going, the action follows some captured savages as they are led to the energy-draining device.
Cliffhanger: I don’t know, (the episode wasn’t over by the time I got to work), but I suspect it was that Steven and Dodo discover the source of the Elders’ power. Unlike on TV, the audio episodes are not a set length, depending on how much non-verbal action there is and how quickly it can be summarized by linking narration. Because I’m able to finish most episodes during my morning commute, I suspect this episode was a bit more verbose than most others.