Doctor Who: The Myth Makers 1965

When the TARDIS arrives on the plains of Asia Minor not far from the besieged city of Troy, the Doctor is hailed by Achilles as the mighty god Zeus and taken to the Greek camp. He meets Agamemnon and Odysseus. Forced to admit he is a mere mortal — albeit a traveller in space and time — he is given two days to devise a scheme to capture Troy. Steven and Vicki, meanwhile, have been taken prisoner by the Trojans. Vicki, believed to possess supernatural powers, is given two days to banish the Greeks to prove she is not a spy.