After the Hole
Guy Burt1993

On a spring day in England, six teenagers venture to a neglected part of their school where there is a door to a small windowless cellar. Behind the door, the old stairs have rotted away. A boy unfurls a rope ladder and five descend into The Hole. The sixth closes the door, locks it from the outside, and walks calmly away. The plan is simple: They will spend three days locked in The Hole and emerge to become part of the greatest prank the school has ever seen. But something goes terribly wrong. No one is coming back to let them out . . . ever.