In an alternative, middle-ages setup, the human population is dwindling in numbers. With the advent of Titans, giant humanoid creatures that attack and devour any human on sight, what remains of civilization is protected by three concentric walls, hundreds of kilometers long and around fifty meters tall.
Eren Jeager, a young boy whose father disappears after his mother is killed during the fall of Wall Maria. Years later he enlists into the army, accompanied by his adopted sister Mikasa Ackerman and their childhood friend Armin Arlelt. He later discovers that he possesses the ability to temporarily transform himself into a Titan. Seen as a threat by some, and a ray of hope by others, Eren joins his companions in a war to protect what still remains of mankind,