Jeremy Bulloch

His spaceship crippled in an inter-stellar battle, the Sontaran warrior, Linx, is forced to crash-land on Earth. He arrives in the Middle Ages, a time too primitive to repair his ship. Allying himself with the local robber chief, Linx uses his powers to 'borrow' scientists and equipment from twentieth-century Earth. Doctor Who tracks down the missing scientists and journeys into the past to save them.