Written by Robert Dunlop

A visit to some caves in a quiet English village turns into a nightmare for the Doctor and Christine when they discover a killer hiding in the dark, an animal which doesn’t even belong to this time.

Investigating further, they find out more than visitors to the caves are meant to know and realise that the town, and even the country, is in danger from a creature, hungry and waiting for food.

The mysterious manager is no help. Does he know more than he’s letting on?

Why is a door mysteriously opening and closing in a supposedly normal cave wall? Is everything as real as it seems?

There’s something else down there…deep, deep down in the rock. Buried and hidden throughout the centuries. But what is it and how can it explain what is happening?

For the two time travellers one thing’s for certain: They’re in danger along with the whole population of Southbank. And if the creature escapes from the caves, will they be able to stop it?

Running time 76 minutes