I have recently watched the 1989 classic Doctor Who episode Battlefield, in which the Seventh Doctor(Sylvester McCoy) and Ace (Sophie Aldred) land near Lake Vortigern in England, and meet Brigadier Bambera of UNIT, Administering a nuclear missile convoy And retired Brigadier Alistair Lethbridge-Stewart. Then Later At the Gore Crow hotel, the Doctor and Ace meet a young woman called Shou Yuing, Meanwhile, Brigadier Bambera encounters two groups of armoured knights. Elsewhere The Doctor discovers a scabbard excavated from the battlefield, on display in a hotel, which an Archaeologist named Warmsly dates to the 8th century, but the Doctor suspects it’s more ancient. Later The Doctor, Bambera, Ace and Shou Yuing find a knight named Ancelyn hiding in the hotel cellar, And are then surrounded by more knights led by a villainous knight named Mordred,
Later Mordred performs an arcane ritual to revive his mother Morgaine Who arrives through a rift in space and time. The next day, Warmsly shows the Doctor where he uncovered the scabbard and They discover a mysterious rune, and a chamber under a lake which is part of an organic spaceship, where they find the body of King Arthur, lying next to a sword, which could be the fabled Sword Excalibur, sadly Ace and The Doctor soon find themselves in deadly peril.
Unfortunately Mordred and Morgaine also learn of Excalibur’s discovery and work out a plan to retrieve It. Later Earth tremors and other strange weather phenomenon start occurring near Lake Vortigern and the Doctor suspects that a powerful evil is at work, so UNIT Troops evacuate the area and Ace is instructed to draw a chalk circle around herself to protect against Morgaine’s sorcery. So Ace and Shou Yuing draw the circle around themselves and Excalibur and stay at the Gore Crow Hotel, however they are confronted by Morgaine, who then summons the Destroyer of Worlds.
Meanwhile Outside an enormous battle ensues between Morgaine’s Knight’s and UNIT troops and amid the carnage Mordred confronts Ancelyn and the Doctor discovers that Morgaine plans to unleash the power of the Destroyer of Worlds if Ace and Shou Yuing, refuse to hand over Excalibur. Eventually The Doctor and the Brigadier manage to capture Mordred, who informs them that Morgaine, now has Excalibur. So The Doctor, Brigadier and Ace pursue Morgaine to her castle, where they face a race against time to stop Morgaine and Mordred’s sinister scheme to destroy the world by unleashing the Destroyer of Worlds.