The first book in the Maze Runner series:
All Thomas remembers is his name as he enters a mysterious place known as the Glade, an encampment found in the middle of a giant maze. He's surrounded by a number of other boys, the Gladers, who are just as confused as he is despite being there for months or even years longer than he has. After the first girl ever to enter the Glade arrives, they're left with a message - they must escape, or they will die.
James Dashner - The Maze Runner