The Doctor and co. are trapped on the war torn planet of Skaro (a planet made exclusively of cardboard and painted murals) and become embroiled in a conflict between the Eloi and the Morlocks.
Though the episode is heralded for being the first ever Dalek story, it has aged like milk. It is not a bad story, but it is padded as fuck, and the Daleks have not been well developed. They are not as fierce and as ruthless as they are in later stories and they sound as if they are on Ritalin . But if you enjoy 40 minutes of the Daleks learning about their own biology and Ian wandering through a poorly lit cave then this episode is your wet dream.