The story revolves Eren Yeager, a boy who lives in the town of Shiganshina, located on the outermost of three circular walls protecting humanity from Titans. In the year 845, the wall is breached by two new types of Titans, named the Colossus Titan and the Armored Titan.
During the incident, Eren's mother is eaten by a Titan while Eren escapes. He swears revenge on all Titans and enlists in the military along with his childhood friends, Mikasa Ackerman and Armin Arlert. He intends to join the Survey Corps, the expeditionary force that seeks to eradicate the Titans from the walls.