Doctor Who tracks down the missing scientists and journeys into the past to save them. But can he defeat the ruthless Linx and his savage human allies before the course of human history is changed forever?
 

Linx, the Sontaran warrior, crash-lands his space-craft on Earth after being crippled by an inter-stellar battle with the Rutans. Unfortunately for him, he's landed in Medieval Wessex, where lufe is primative and the technology to repair his ship hasn't been invented yet. He allies himself with the local bandit-chief Irongron, and builds a crude time-machine in order to snatch the people and equipment he needs from the twentieth century. Meanwhile, The Doctor, who is searching for these missing scientists, transports himself and Sarah Jane to their place of capture - the foul medieval lair of Irongron's castle, where the axe meets the ray-gun, in the hostile environment of the Middle Ages.

This was the first Doctor Who TV adventure which featured Elisabeth Sladen as Sarah Jane the stowaway reporter, and revealed the name of the Time Lord's planet, Gallifrey.
 

Linx, an alien Captain of the Sontaran race, lands his starship crippled by the Rutans, in medieval times outside a castle belonging to the robber chief, Irongron. Irongron offers shelter in exchange for modern weapons. Linx uses his time machine to reach the 20th Century to steal scientists and equipment to repair his startship. The Doctor, accompanied by a stowaway, journalist Sarah Jane Smith, who is investigating the disappearance, uses tracking instruments to find Irongron's castle. The Doctor is captured and interrogated by Linx, who discovers he is a Time Lord. Despite the resistance of a robot knight built by Linx, Irongron's castle eventually falls. Linx is killed by a local archer and his spaceship blows up.

Running time: 91 mins approx.

Produced by Barry Letts
Directed by Alan Bromley