The maze runner - James Dashner

When the doors of the lift crank open, the only thing Thomas remembersis his first name. But he's not alone. He's surrounded by boyswho welcome him to the Glade - a walled encampment at the centreof a bizarre and terrible stone maze. Like Thomas, the Gladersdon't know why or how they came to be there - or what's happenedto the world outside. All they know is that every morning whenthe walls slide back, they will risk everything - even the Grievers,half-machine, half-animal horror that patrols its corridors,to find out.