homas is brought into a place known as the Glade with no previous memories of his life or the outside world. All he remembers is his name. He and about 50-60 other teenage boys inside the Glade call themselves Gladers, and have developed a community in which every Glader is assigned to his own job. The Glade is surrounded by a giant Maze where vicious, slug-like creatures with mechanical like arms, named Grievers, roam at night. Massive walls called the Doors surrounding the Glade protect the Gladers from these creatures by sliding closed every night.

Every week, supplies are brought to the Glade and once a month a new boy is sent up through an elevator called the Box. The day after Thomas is brought to the Glade, a girl is sent with a message claiming she is the "last one ever." A girl has never been brought in before and the Gladers are excited and confused by her unexpected arrival. Immediately after arriving, the girl falls into a vegetative state.

Meanwhile, Thomas learns more about the Glade, and he feels at home like he's been there before. He learns that the Gladers have been trying to solve the Maze for two years and that the Grievers sting can cause you to recall almost complete memories from the past. The process is painful and dreaded by other Gladers. He feels oddly connected to the new girl and also befriends a young Glader named Chuck, as well as a boy named Newt. On the other hand, he has a somewhat negative relationship with Gally, who is suspicious of Thomas and claims that he has seen him, after he was stung by a Griever, in a process known as the Changing. Thomas also feels an inexplicable urge to be a Runner, the people who explore, map out, and try to find a way out of the Maze.

One day, one Runner and the "leader of the Glade," Minho and Alby return late from the job. Alby has been stung by a Griever. As the doors are about to close with Minho and Alby outside, Thomas runs to join them in the Maze. Hearing the approaching Grievers, Minho tells Thomas that they must split up and run away, leaving Thomas with an unconscious Alby. Thomas manages to save Alby by tricking the Grievers into falling off the edge of the Maze, aka the Cliff. Minho realizes Thomas could be the best Runner they have and the two become friends.

The next morning, the three arrive back in the Glade as the doors open to the amazement of the fellow Gladers. As acting leader, Newt decides to call a gathering to decide the fate of Thomas for breaking the first rule of the Glade. During the meeting, Gally again declares his suspicions about Thomas. Others, however, defend Thomas. Minho suggests Thomas replace him and be made the keeper of the runners.

It is decided that Thomas be made a Runner. Minho and Thomas set out for the maze and the two find a transparent hole which leads to what Thomas calls the Griever Hole. Gally also goes missing around this time. After returning to the Glade, Thomas is shocked to hear the girl speak telepathically to him. He realizes her name is Teresa and she tells him she has "triggered the Ending". Soon afterwards, Teresa wakes up from the coma and finds Thomas. The two begin to talk and realize they feel connected to each other in a way that is close to remembering their lives before the Glade. The same day Teresa wakes up, the sky turns a dull grey. Thomas realises that it must be fabricated by the Creators who put them in the Glade. That night, the Doors do not close, meaning the Gladers are completely unprotected from the Grievers.

After Alby has gone through the Changing, he talks about the outside world and how it is far worse than any of them could imagine. Alby recalls Thomas and begins to speak about his memories. During his conversation with Thomas, Alby suddenly starts choking himself and Thomas calls on Newt to help subdue Alby. The Gladers go into a state of siege and Gally returns in a hysterical state, telling the Gladers that one of them will die every night. After the Grievers enter the Glade, Gally throws himself onto one and the Grievers retreat. It is discovered that all the Maps of the Maze made by the Runners over the past two years have been burned. Thomas is discouraged as he and Teresa had had an idea about the maps revealing a code, allowing the Gladers to find a way out. After Thomas voices his distress at the maps being burnt, Newt and Minho tell him that they hid the Maps in the Weapons Room in case something like this happened, and that they left decoys. With Teresa, Minho and Newt’s help, Thomas finds a code in the Maps, but they are all unsure of how to use it.

Desperate for answers, Thomas decides that he must be stung by a Griever to use any memories revealed in the Changing. When he wakes up after the Changing, he realises that the Maze was never meant to be solved, but that they have been placed in a kind of experiment by the Creators to test their strength. He tells the other Gladers that they need to go down the Griever Hole and enter the code in a computer. After some deliberation, most of the Gladers decide to go through with the plan, and after preparing, they enter the Maze for what they hope is the last time.

Upon reaching the Hole, they realize that the Grievers are waiting for them. The Gladers attack the Grievers while Thomas, Teresa and Chuck attempt to get to the Hole. They eventually get through and Teresa enters the code while Thomas and Chuck fend off the Grievers. After entering the code, the Grievers are shut down and the remaining Gladers join them. About half of the Gladers who chose to fight were killed.

A door opens at the end of the Hole and the Gladers, including Thomas, Teresa, Chuck, Minho, Newt exit to find the Creators. A woman comes to greet the Gladers, but they feel hostile towards her for putting them through the test. She is joined by a hooded figure who is revealed to be Gally, and as a final part of the test, he pulls out a knife from his pocket and throws it at Thomas. Before he can react, Chuck throws himself in front of Thomas. Thomas attacks Gally before breaking down in tears, since he had promised Chuck he would get him back to his family.

Suddenly, a group of armed people rush into the building and attack the Creators. The leader says there is no time to explain and asks the Gladers to follow him to a bus. Before Thomas can get on, a woman grabs him, saying "You have to save us from the flare!", but is dragged away. Thomas gets on the bus and the leader runs the woman over. The Gladers are taken to a dormitory where they are fed and given a comfortable safe haven for the time being.