| This article is incomplete.|
Please feel free to edit this article to add missing information and complete it.
Specifically, it needs Japanese release date.
While there is a festival outside celebrating the sealing of the Walls, Mikasa realizes that she can not remember what Eren looks like, and rushes out the door in hopes of seeing his face one more time. As Mikasa runs through the crowd of people outside she gets shoved and pushed to the ground.
Mikasa is grabbed off the floor by a masked man calling himself Mirror Man, who urges onlookers to watch him turn Mikasa into a murderer. The man tells her that she must kill him if she wants to see Eren again. Mikasa hesitates but proceeds to stab the man with a knife he gave her. The Mirror Man reveals to the festival goers that he was not truly stabbed, but he still succeeded in turning a little girl into a killer.
The Mirror Man lets Mikasa go, and she starts to regret not stopping Eren from leaving. She walks back to Eren's house and looks in the window to find Grisha, Carla, her parents, and her newly-born baby brother. Armin arrives out of breath and informs Mikasa that the plane had crashed into the wall, killing Eren. Mikasa finally awakes from her dream and encounters two Titans. As she readies herself to fight one of Titans, the other Titan behind her punches the first Titan.
As Mikasa sits alone in her room watching the butterfly Eren gave her, she notices a festival is going on outside. Mikasa overhears several festival goers celebrating the sealing of the Walls, and the disbandment of the Survey Corps, which makes her think about Eren. She is suddenly horrified by the realization that she has forgotten what Eren’s face looks like. Worried that she might never see Eren’s face again, she runs through the crowd in hopes of getting to see Eren one last time. As Mikasa runs through the crowd she gets shoved and pushed to the ground. As a result, one man spills his booze onto Mikasa and another man picks a fight with them.
A masked man then grabs Mikasa's arm and pulls her up. The man urges the crowd to look at him as he attempts to turn Mikasa into a murderer, but everyone is busy watching the fight. He tries once again to attract the attention of the crowd and introduces himself as the Mirror Man. Giving up, he turns to Mikasa and begins to talk to her. Mikasa begs him to let her go so that she can see her friend but the masked man refuses, explaining to her that he needs to hypnotize her into becoming a murderer. The man hands her a knife, and proposes a deal to her, if she murders him right then he will let her go.
The man starts to tell Mikasa about how the world is an unfair place by giving the example of humans eaten by Titans. He then explains to her that he is tired of going around from festival to festival, performing over and over again. By hypnotizing Mikasa into killing him it would be his greatest, and final act, serving as his revenge on the world. Mikasa stays silent, causing the Mirror Man to grow impatient and telling her that if she does not act soon, she will never see Eren again. Mikasa is shocked to learn that the Mirror Man knows Eren, and starts to question the man about who he is. He tells her that he is no one but could be anyone at the same time. He says that he knows that she is lost, and advises her to go back to where she came from before it is too late. Mikasa struggles to decide if she wants to stay in this world or kill the man to see Eren again, but after some hesitation, she decides to stab him.
Before she can stab the man, Mikasa is interpreted by a loud booming sound. As the festival-goers try to locate the source of the sound, a lady starts screaming. They look over to see what the commotion is about and are shocked to find the Mirror Man knelt lifeless on the ground with a knife in his chest, and blood all over Mikasa. All of a sudden the Mirror Man starts laughing and reveals that he is actually unharmed. Nevertheless, the Mirror Man succeeded in turning Mikasa into a killer. The crowd starts applauding and the Mirror Man lets Mikasa go.
Mikasa gives up on seeing Eren again, believing that he has already left, and starts to walk home. On the walk home, she starts to regret not stopping Eren from leaving. As she reaches Eren's house she looks in through the window to find Grisha, Carla, her parents, and her newly-born baby brother. As it starts to rain a young boy runs around the corner, soaking wet, and out of breath.
Mikasa recognizes the boy as Armin Arlert despite only meeting him for the first time. Armin falls to his knees and informs Mikasa that the airplane failed. He tells her that Eren saved him by pushing him out of the plane before it crashed into a wall. Armin starts blaming himself for telling Eren about the outside world and apologizes to Mikasa. In shock, Mikasa finally awakes from her dream and finds herself laying on the top of a fruit stand. As Mikasa jumps to the ground, two Titans start approaching her from either side. She starts to think about her memories with Eren, and remembers Eren urging her to fight. As she readies herself to fight one of Titans, the other Titan behind her punches the first Titan.