The series follows the story of Eren Jäger (a teenager boy), his adopted sister, Mikasa Ackerman, and their friend Armin Arlert (Emotional blond baby). They live in a world after the apocalypse caused by man-eating human-like giants called Titans, and they're members of what is likely the last surviving bit of civilization. Their civilization is surrounded by three protective walls called Wall Maria, Wall Rose, and Wall Sina. Eventually, Wall Maria, the outermost wall, is destroyed by the skinless Colossal Titan and the powerful big Armored Titan, leading other titans to infiltrate the outermost areas of civilization and begin their slaughter. The destruction that was caused by the titans kills Eren's mother and he vows revenge against the Titans. Eren enlists in the military and is also accompanied by Mikasa and Armin. Years after his first battle against the Titans, Eren finds out that he has the ability to transform into a Titan at will. After others found this out, Eren was seen as a threat to mankind by some but was also seen as a chance of hope by others. He later joins his companions to fight and protect what remains of their society while he also looks for answers to the mysteries surrounding the Titans, the Walls, as well as his own existence.