Beginning its four-episode run on November 25, 1978, "The Androids of Tara" was a follow-up to the previous Doctor Who adventure "The Stones of Blood." In search of the fourth segment of the Key to Time (which, when reassembled, will restore the balance between Good and Evil), the Doctor (Tom Baker) and Romana (Mary Tamm) arrive on the arborial planet Tara, which still exists in the Middle Ages. In retrieving the fourth key, Romana has an easy time of it -- deceptively easy, as it turns out. "The Androids of Tara, Episode 1" was written by David Fisher.
by Hal Erickson synopsis