Stephen King had an alter ego for awhile. His name was Richard Bachman. His view of the world was a little darker than King's. The Long Walk is one of his novels.
Just like King, Bachman realizes that a scary story does not have to be big. It does not have to deal with the supernatural. It only has to include the most terrifying species on the planet: humans. Nothing is scarier than the things we do to ourselves and each other.
This book is a simple story. 100 boys set out to see who can walk the furthest without stopping.
Here's the catch. We're in a slightly altered world where the US is run by the Major. For a reason not explained in this novel (it reminds me of the blood tribute in Crete), he has started the tradition of a long walk every year. 100 boys walk until they can't anymore. After three warnings for dropping below a designated walking speed, they get their ticket. The last boy walking gets the prize. Whatever he wants for the rest of his life.
The prize is what gets the boys to start walking in the first place. The fascinating part of this novel is what keeps them walking.
Of course, there is no guarantee that the winner will be in any shape to enjoy his prize....