"The seal must not be broken. What's inside must not get out."
The 10th century A.D.
Fanatical Christians rebelling against the Pope dig deep into the Earth in a quest to find Hell. And for a thousand years, they kept on digging.
The present day.
A group of American college students stranded in England descend into an abandoned medieval mine, where they encounter a hellish nightmare world.
Getting in was easy. Getting out will unleash Hell on Earth.