Doctor Who: The Stones of Blood, Episode 4 on AllMovie

In the conclusion of the four-part story "The Stones of Blood," archeologist Vivien Fay (Susan Engel) has revealed herself to be the Cailleach, a 4,000-year-old pagan goddess. Determined to prevent the Doctor (Tom Baker) from retrieving the third segment of the Key to Time from a Druidic stone circle, the Cailleach kidnaps Romana (Mary Tamm) and heads off to deep space. In his efforts to rescue Romana, the Doctor accidentally unleashes a fearsome fleet of "justice machines" called the Megara -- and for a while, it looks as though the reconstruction of the Key and the ultimate restoration of the balance between Good and Evil will never come to pass. First telecast November 11, 1978, "The Stones of Blood, Episode 3" was written by David Fisher.