I have recently watched this classic Doctor Who episode starring Jon Pertwee and Elizabeth Sladen. It begins In the Middle Ages, when the Cruel Warlord Irongron and his Master-at-Arms Bloodaxe, together with their rabble of criminals, discover the crashed spaceship of a Sontaran warrior named Commander Linx, who strikes a bargain with Irongron and offers him high tech weapons which will allow him to conquer his neighbours and become king, in exchange for materials and help with which to repair his ship and return home.
Meanwhile back in the present day scientists are mysteriously vanishing from a top secret research complex and The Doctor and Brigadier Lethbridge-Stewart (Nicholas Courtney) of U.N.I.T. are called in to investigate. The Doctor discovers that a Sontaren Commander is at large and has kidnapped the scientists by means of an Osmic Projector which has allowed him to project himself 800 years into the future, from the Middle Ages to the present day and kidnap and brain wash the scientists into helping him rebuild his damaged spaceship. While investigating The Doctor meets an eccentric scientist called Rubeish and a inquisitive young journalist called Sarah Jane Smith, (Elizabeth Sladen), who has infiltrated the complex by masquerading as a Scientist. Later that evening Rubeish also disappears and the Doctor follows the trail back to the Middle Ages, unaware that Sarah-Jane has also stowed away on board the TARDIS.
Irongron comes up with a devious plan to attack and take Wessex Castle from Lord Edward of Wessex using the high-tech weapons supplied by Linx, so Lord Edward sends an archer Named Hal on a mission to Assassinate Irongron. Meanwhile Sarah Jane is captured and brought before Irongron. Linx constructs a Robot Knight which is dispatched to deal with Hal, but is prevented by timely intervention by The Doctor. In The ensuing confusion both Hal and Sarah flee to Weesex Castle. The next morning irongron and his troops attack the castle using the high-tech weapons supplied by Linx.
Later The Doctor and Sarah-Jane infiltrate the Castle disguised as monks and find Rubeish and the other scientists in a state of extreme exhaustion. Sadly Linx also catches them in the Laboratory however an intervention by Rubeish renders Linx temporarily immobile after he strikes his Probic Vent – a Sontaran refuelling point on the back of their necks which is also their main weakness. The Doctor then uses the Osmic Projector to send the scientists back to the twentieth century. Meanwhile Sarah-Jane comes up with a plan to incapacitate Irongron and his men. Upon recovery Linx decides to depart from the castle in his Shuttle, The Doctor and Hal however have other ideas and try to prevent his leaving with explosive results….