Romana discovers an alien device that proves Vivien is not human. They lure the Ogri back to the projector, and she and the Ogri return to the spacecraft. On the ship, the Doctor learns the Megara are seeking a criminal known as Cessair, who had stolen the Great Seal of the planet Diplos, which grants its bearer great powers. The Doctor suspects Vivien is Cessair, and attempts to force the Megara to question her, but their law prevents such intervention. Having decided the Doctor's guilt, they fire an energy weapon at him, but at the last moment, the Doctor drags Vivien into the shot. The Megara immediately stop their attack and scan Vivien to see if she is unharmed, but instead discover that she is Cessair. Romana arrives with the additional evidence, and the Megara pass judgement on her. They return her to Earth and transform her into a standing stone in the moor, but not before the Doctor recovers the Great Seal which she wore. The Megara are about to pass judgment on the Doctor when they're forced to return to their ship and depart to Diplos. The Doctor had set the controls of the ship before leaving, and he affirms the Great Seal is the third segment of the Key, and he, Romana, and K9 thank Emilia for her assistance before they leave in the TARDIS. She smiles as she now has a new stone in the circle to study. Productions Working titles for this story included The Nine Maidens and The Stones of Time. Contrary to usual practice, the location footage in this story was shot on professional video cameras using outside broadcasting facilities, a decision by the director to avoid the jarring effect when cutting between 16mm film and video. The main location was the Rollright Stones, a megalithic site in Oxfordshire, England. The setting of the story however was Boscawen, in Cornwall, at the Boscawen-Un stone circle. An actual legend of the site states that it is impossible to count the stones. As the serial ends, the Doctor notes that the number of stones in the circle has changed (due to the removal of 3 Ogri and the addition of Cessair's imprisoned form) and suggests Professor Rumford write a monograph about it. Part One's cliff-hanger called for a scene in which Cessair, disguised as the Doctor, pushed Romana off the cliff. Baker objected to the