On a lonely stretch of Welsh coastline a fisherman is killed by a hideous creature from beneath the waves. When the Doctor and Rose arrive, they discover a village where the children are plagued by nightmares, and the nights are ruled by monsters. The villagers suspect that ancient industrialist Nathanial Morton is to blame, but the Doctor has suspicions of his own.
Who are the ancient figures that sleep in the old priory? What are the monsters

1500BC - King Actaeus and his subjects live in mortal fear of the awesome gods who have come to visit their kingdom in ancient Greece. Except the Doctor, visiting with university student June, knows they're not gods at all. They're aliens.
For the aliens, it's the perfect holiday - they get to tour the sights of a primitive planet and even take part in local customs. Like gladiatorial games, or hunting down and killing humans who won't be missed.

The old village well is just a curiosity - something to attract tourists intrigued by stories of lost treasure, or visitors just making a wish. Unless something alien and terrifying could be lurking inside the well? Something utterly monstrous that causes nothing but death and destruction?
But who knows the real truth about the well? Who wishes to unleash the hideous force it contains? What terrible consequences will follow the search for a