The Doctor and his companions uncover the dark secret behind the City's Utopian facade: the exploitation of the primitive people for energy.

The Doctor, Dodo, and Steven materialize in the TARDIS after landing on a planet the Doctor declares a 'future of peace and prosperity.' As he prepares to leave the TARDIS, …

In the sterile, high-tech Control Room, Nanina—already restrained on a trolley—pleads desperately for mercy as Senta, the coldly efficient chief scientist, orders her removal with clinical detachment. Her frantic cries …