|Doctor Who-The Stones Of Blood|
Understanding this is no mere terrestrial problem Romana goes to investigate,only to be whisked away to a place unknown by Vivian Fey. Meanwhile the doctor,Rumford and K-9 rig up a special device that reveals the location of Romana and Vivian to be in hyperspace,another dimension occupying our own past the spectrum of the speed of light. Aboard a prison ship found there,the Doctor and Romana unknowingly break the seal for the confined Megara,machine judges who plan to execute the doctor for his unknown crime. Upon conducting a fair trail in his defence,the doctor is able to reveal Vivian Fey to be the extraterrestrial criminal Cessiar Of Diplos,who the Megara have been pursuing. After justice (of sorts) prevailing it's learned that the Cessiar,now eternally imprisoned as one of the autonomous stones she used as weapons,was actually carrying the third segment of the key as a pendant. The doctor and Romana then bid Rumford farewell with the key in hand.
Stories such as this revolving around unknowingly extraterrestrial based religious orders would be pursued heavily later on programs such as The X-Files and become a common theme in sci fi and fantasy TV. It's a very well executed concept and story,with a compelling mystery that unfolds. It's the character of Professor Rumford who is the most memorable. She has a charming and humorous relationship in particular with K-9,and a mildly flirtatious one with the doctor. With her willingness to assist the doctor in unraveling the mystery and saving Romana from her hyperspace prison. She actually is one of those one off characters who would've been a fine companion for the doctor. In terms of the companion involved,by this point we find the usually steely Romana beginning to develop more of a trust in the doctors abilities and effectiveness. And that trust is inevitably what brings the story to a successful conclusion.