What is the idea or purpose of this story?

This is very much a thematic question. Check out the GradeSaver themes page below:

http://www.gradesaver.com/the-maze-runner/study-guide/themes

The main character, Thomas, wakes up in a box that arrives in a place called "The Glade" he finds himself surrounded by a maze that changes and rotates everynight. He and the other people that arrived in The Glade have to find a way to escape.

Followung the events in the maze...finding a cure to the sun flares and trying to survive WICKED in the meantime...