Prologue arc

The Fall of Shiganshina arc is the first story arc of the Attack on Titan series. The story begins inside the walls of humanity and the main protagonists are shown, Eren Yeager, Mikasa Ackerman and Armin Arlert. However, a mysterious threat known as the Titans lurks outside these walls and the children soon learn of their terror as the Colossal Titan breaks through the gate to their home, Shiganshina District.

Summary
Outside the Walls, the members of Survey Corps are seen running forward on horses. One of them orders everyone to get ready to fight, having a single target. Erwin Smith notices the target approaching and the formation splits into several groups of decoys and attackers. Using their Three Dimensional Maneuver Gear, they reach the Titan in an attempt to attack it.

At unknown time in year 845, a young boy named Eren wakes up inside Shiganshina District. A girl named Mikasa tells him to head home as it's about to get dark. Eren notes that he was having a really long dream and when Mikasa looks at him, she notices that tears are flowing down his cheeks. As they are on their way home, Eren insists that Mikasa tells nobody that he was crying. Mikasa remarks that he should let his dad take a look at him if he had tears in his eyes for no reason, but Eren rejects this idea. Suddenly, a soldier named Hannes appears behind him, asking if Eren was crying because Mikasa was mad at him. Eren is disgusted to see that the soldiers are drinking again and asks about their work. Hannes confirms that they're watching the Walls today and when Eren questions how they're going to fight the Titans if they're drunk, one of the soldiers states that not even once in 100 years the Titans have managed to break through the gate. Eren continues complaining about the fact that the soldiers have no will to fight and states that they're living like a caged livestock. Picking up this piece of information, Hannes wonders if Eren is planning to join the Survey Corps, a branch of soldiers that venture outside the Walls.

The kids continue walking when Mikasa states that Eren shouldn't join Survey Corps. Before she can explain herself, they hear bells signalizing the return of the Survey Corps forces, prompting Eren and Mikasa to run to that direction. They notice that the number of the soldiers has decreased, with the remaining ones being injured as well. Suddenly, an old woman approaches the soldiers, looking for her son. However, she is given a man's arm, supposedly the only remainder of her son's body. The woman breaks down and then begs the soldier to tell her whether her son was of any help. Taken aback, the soldiers confirms it at first, but then cries out that the whole expedition was for nothing, having made no progress at all.

Afterwards, Eren gets annoyed when bystanders start insulting the Survey Corps, but is then grabbed by Mikasa and taken away. She then asks him if he had changed his mind about joining the Survey Corps, but gets no reply from him. Later, they finally arrive to their house. Mikasa reveals to the parents that Eren plans to join the Survey Corps, much to the discontent of Eren's mother, Kalura Yeager. When questioned by his father, Dr. Grisha Yeager, Eren states that he'd hate to spend his life inside the Walls and someone has to take on their job, otherwise all the soldiers would have died in vain. Grisha then gets ready to leave, stating that when he returns, he will show Eren the basement of their house. Kalura, however, decides to continue arguing against Survey Corps, which angers Eren, causing him to leave.

Elsewhere, a young boy, Armin, is seen getting beaten up by three boys because, as Armin states, they know he is right. Just as he is about to get hit, Eren appears, much to the boys' amusement. However, as they realize that Mikasa is with Eren, they run away. Later, Armin explains that they were beating him up because he claimed that humans eventually need to get outside. This leaves Eren annoyed due to the fact that they get looked down for desire to go outside, but Mikasa argues against it. Armin shares his thoughts, claiming that even though the Walls have been intact for 100 years, there's no guarantee that they won't be broken down today.

At that moment, the ground shakes and they hear a loud noise. Rushing to see what happened, they see part of the wall covered by smoke. The kids then notice a hand on top of the wall, leaving them shocked as the wall is 50 metres tall. A face of the Colossal Titan then emerges. Kicking through the gate, other Titans can now enter the Shiganshina District, much to the shock and horror of the people. Armin wants to run away, but Eren runs towards the opposite direction, to where his house stands. Followed by Mikasa, Eren reaches the location just to see their house destroyed. With Kalura trapped inside, Eren and Mikasa attempt to move the pillar away, but suddenly a loud noise is heard and a Titan is seen reaching their place. Seeing this, Kalura begs the kids to get away, but Eren and Mikasa refuse to leave her.

Suddenly, Hannes arrives, taking out his blade to fight the approaching Titan. However, Kalura begs him to take the kids and get away. Upon witnessing the Titan's face, Hannes grabs the kids. Just as they run away, the Titan reaches Kalura and the kids watch in horror as she gets eaten alive. Some time later, Eren snaps out of it and hits Hannes in anger. Hannes tells him that he couldn't save Eren's mother because he was afraid and asks for forgiveness just as Mikasa feels reminiscent.

The kids get on a ship in order to evacuate just as Hannes begs the soldiers not to close the gate yet to let more people inside. However, the soldiers witness the Armored Titan approaching. The Titan accelerates and begins running towards the gate and the soldiers realize that their weapons have no effect just as the Titan manages to break through, successfully destroying the gate and letting Titans inside the Wall Maria. Seeing this, Eren realizes that he can never go home again. Angered and crying, Eren vows to exterminate all the Titans.