The Doctor and Ace discover a stone spaceship underneath Warmsley's archaeological dig while Mordred summons Morgaine to Earth's dimension.
Quest roles:
Nicholas Courtney(Brig. Lethbridge-Stewart), Jean Marsh(Morgaine), June Bland(Elizabeth Rawlinson), Marcus Gilbert(Ancelyn), James Ellis(Peter Warmsly), Angela Douglas(Doris Lethbridge-Stewart), Christopher Bowen(Mordred), Angela Bruce(Brigadier Winifred Bambera)