|In the end, I couldn't... I couldn't change a single thing at all. I'm a mere bystander.|
|— Keith Sadies on Eren Jaeger following in his father's footsteps|
Two months have passed since Historia Reiss' coronation. She has started a farm to take care of the orphans and the needy. The military has also been overhauled. They now have a new weapon that allows them to kill Titans without risking the lives of soldiers and new recruits have joined the Scout Regiment. At Jean Kirschtein's prompting, Eren Jaeger tries to remember the Scout who appeared in his father's memory and realizes that it is Commandant Keith Sadies of the Cadet Corps.
Eren, his squad, Levi, and Hange visit Keith and hear his story of how he discovered Grisha Jaeger outside of Wall Maria twenty years ago. The two became friends, and Grisha inspired Keith to think he was special. However, Keith suffered many failures, both in his personal life and as an officer, and came to realize he was not special at all. He was with Grisha the night Wall Maria fell, and carried Eren out of the woods after Grisha had taken him there. Keith hoped that Eren would avoid becoming like his father, but even though he sabotaged Eren's training gear when he was a cadet, Eren would not give up. As Eren leaves in the present day, Keith realizes he could not change anything.
On a rural farm, Historia Reiss chases after a pair of children as Eren Jaeger, Armin Arlelt, and Jean Kirschtein watch. It has been two months since she was crowned, but she seems better suited to run an orphanage than a country. Armin says that people are affectionately calling her the "Cattle-Farming Goddess." Jean comments that at this rate, no one will remember the chump who plugged the hole in Trost District, but to his disappointment, Eren does not take the bait and talks about how this is what Historia wished for, to take care of the orphans and the needy.
Historia then runs up to them and tells them to stop slacking since it is getting dark. Jean and Armin reluctantly obey. Eren does not seem bothered though, and walks alongside Historia. He confirms that his hardening experiments are going well, but they need to hurry before they return. She asks him what he would do if he had to face Reiner Braun and Bertholdt Hoover again. Eren replies that he would have to kill them.
Downcast, Historia tells him that she does not want to regret what they have done. The children from the underground are smiling and she cannot see that being the wrong choice. Eren says she has been doing great, to her embarrassment, and mentions that she was originally the one who said humanity should get wiped out. She protests that she was merely getting carried away, but before the conversation can proceed further, Mikasa Ackermann shows up with a scary expression on her face. She takes away Eren's load of supplies, saying that he is tired from his experiments, and carries it away herself. Eren complains that she should stop treating him like an old man.
Meanwhile, the military has undergone a purge, following the coup d'état, but humanity has also gained things in return. The glowing ore from the Underground Chapel can now be used as a light source, and thanks to Eren's hardening experiments, they were able to create a new anti-Titan weapon, which Hange Zoë calls the executioner from hell during a public demonstration.
It works by luring Titans into a narrow corridor to try reaching a human blocked by strands of Eren's hardened Titan material. Once the Titan is wedged into place, the Scout Regiment drops a log on the nape, killing it.
Hange is overjoyed to see that the weapon works, since this will allow them to kill Titans day and night without risking the lives of any soldiers, but when she turns to share her excitement with Eren she sees that he is bleeding out from his nose. Levi Ackermann tells her that he has probably been overusing his powers with all the hardening experiments and Hange apologizes. Eren dismisses it though. He wants these weapons made so they can hurry on to Shiganshina District.
Later on, in the Scout Regiment mess hall, Marlo Freudenberg shares his exuberance with members of Squad Levi. He is confident that the new weapons will allow them to eliminate the Titans. Unimpressed, Jean says Marlo is the only person who would be this excited over joining the Scouts. After Sasha Braus questions Marlo about why Hitch Dreyse did not try to stop him, Marlo wonders why she would. But he does recall that she told him pretty adamantly not to join and he said he was wrong about her. Jean, Armin, and Sasha all comment on how thick-headed he is, with Eren being the lone outlier who does not understand what Marlo did wrong.
Steering the conversation back to work, Jean informs Marlo that the only people who are getting worked up by their progress are the new recruits like Marlo, who have no prior combat experience. From another table behind him, Floch asks if Jean thinks of himself as a veteran now. He comes over to Jean's table along with a couple other recruits and says that they are not the only ones who are excited. Everyone in the Walls is looking forward to taking back Wall Maria. But looking at his fellow graduates of the 104th Cadet Corps, Floch realizes there is something different about them. There is something in their faces that makes him wonder what happened to them. Jean asks him if he would like to know, and Floch decides to decline.
After Floch and his companions leave, Conny Springer gets up, saying that he is going to visit his village in the morning. Sasha supposes that it is not possible to make Conny's mother human again and Armin agrees. This causes Eren to remember Ymir and what she said it was a like being a Titan. He wonders if Titans are simply people tormented by nightmares.
Before he can wallow too deeply in the memory of when he was a Titan himself, Mikasa snaps him out of it and tells him to finish his food. Jean also complains about Eren's morose mumbling and tells him that he should focus on remembering the Scout he saw in his father's memories. Eren feels that he has met that man before, but cannot remember where. Jean tells him that maybe what he needs is a headbutt from the commandant, which causes Eren to realize that the Scout in his father's memories and Commandant Keith Sadies are the same person.
Keith Sadies was the 12th Scout Regiment Commander and led them before Erwin Smith. Hange, Levi, and the Special Operations Squad go out to meet him on the training grounds. When they are seated inside, Sasha insists on standing, still terrified of the time she spent in training. Keith notes that even though it has only been months since they graduated, he barely recognizes the 104th anymore.
Hange asks if Keith understands why they are here. Rather than answering, Keith looks at Eren and says that he resembles his mother, but the fangs in his eyes are from his father. Eren asks that Keith tell them everything, and Keith admits that in the grand scheme of things he does not know anything, but agrees to tell them what he knows in his personal history as a bystander.
Keith met Grisha twenty years ago outside the gates of Wall Maria. Both were shocked to find the other outside the Wall; Keith because Grisha somehow got outside, and Grisha because that meant Keith was trying to fight. Grisha could not remember how he got outside, but Keith brought him in.
Once there, Grisha was detained by the Garrison since it is a crime for ordinary people to go outside the Walls, but Hannes was ambivalent about keeping him because it was not as though Grisha had hurt anyone. Hannes suggested not reporting Grisha and Keith agreed.
Grisha claimed to have lost his memories, but in addition to his name, he said he remembered being a doctor and asked if he could be introduced to a hospital where he could find work. He also asked if Keith could teach him about this world and the Scouts. Keith taught him, but was surprised that Grisha truly did not know anything about the state of the world.
While they drank at a bar, Grisha expressed relief that the people of the Walls did not live in fear of the Titans, but Keith was unhappy with the sentiment. Unlike other people, Keith did not think it was enough to live safely behind the Walls. There was a world out there and he affirmed that exploring it was what he and the Scouts do. Keith asked if Grisha thought that was foolish, but Grisha found it admirable, calling the Scouts the pride of humanity.
Carla interrupted them, asking if Keith was trying to recruit for the Scouts again, and Grisha politely said that was not the case as he was unsuitable for it. Only a chosen one could do that kind of work, a notion that Keith took to heart.
As the Scouts suffered repeated failures under the 11th Commander, Keith began to think he would achieve results if only he was in that role himself.
Sometime later, a plague gripped Shiganshina and Carla caught it. Keith brought her to Grisha for medical care and when she said her parents were sick too, Grisha assured her he would care for everyone. Keith could see her growing closer to Grisha, and his own promotion to Commander of the Scout Regiment was overshadowed by the marriage of Carla to Grisha.
After returning from an expedition, the Scouts talked around Keith's back about him being a moron who charges into death and wishing that they could change commanders for Erwin, since his squad did not suffer any casualties. Keith reminded himself that he was special, chosen, as he walked through town and eventually bumped into Carla with an infant Eren. She asked Keith if he intended to keep this up until he died and began to suggest that he should retire, but this struck a chord in Keith.
He launched into a tirade about how most people live and die without changing a thing. Normal people cannot accomplish greatness. And this caused him to, years later, ask Erwin to take over for him as commander. Keith became certain that special people did exist, but after all of his failures, it was clear he was not one of them. He just did not realize it.
Keith was in Trost District when Wall Maria fell and while there, met up with Grisha. When the refugees eventually arrived, Grisha and Keith found Eren and learned about Carla's death. Grisha then told Eren that he would have to avenge his mother and took him away. He told Keith not to follow, but Keith asked Grisha why he would not avenge Carla himself. Though Grisha was special, Eren might not be. Grisha informed him that Eren was different from Keith, because he was his son, and again asked that Keith stay out of it. Keith did.
When dawn came, Keith saw a lightning flash in the woods and heard thunder. He found Eren by himself, unconscious, and he carried him back to the shelter where he put him in bed beside Mikasa and Armin. That was the end of his story.
Hange is disappointed to learn the real reason for Keith's resignation was not to atone for the soldiers who died under his command, but because he felt he was not special. She calls out his inferiority complex and tells him not to run from reality. Though she gets worked up, Eren asks her to calm down. Eren feels that Keith is right, and that he, Eren, was never special either, but he knows he is the son of a special man.
Keith offers Eren one final memory. When he had ranted about specialness to Carla, she asked him if it was wrong to not be special. She did not think so. Carla did not need her son to be better than anyone. He was already special just for being born into this world.
As Eren and company leave, Keith remembers how he sabotaged Eren's training gear when he was a cadet so he would not be able to balance, but despite that Keith could not force Eren to flunk out of the Cadet Corps.