After a strange toxin contaminates the water supply in a small town in Iowa, the residents are suddenly turned into bloodthirsty psychopaths. The town sheriff does all he can to make sense of the outbreak, as his wife and two other unaffected people fight for their survival.

In the epic finale to the saga, Thomas leads his group of escaped Gladers on their final and most dangerous mission yet. To save their friends, they must break into the legendary Last City, a WCKD-controlled labyrinth that may turn out to be the deadliest maze of all. Anyone who makes it out alive will get answers to the questions the Gladers have been asking since they first arrived in the maze.