|Finally, we're back... The first time... since we fled from here.|
|— Armin Arlelt, to Eren Jaeger and Mikasa Ackermann|
The Scout Regiment arrives in Shiganshina District only to discover it is completely devoid of Titans. Eren Jaeger successfully plugs the outer gate leading to the exterior of the Walls, using his Titan's hardening ability and without encountering any enemy resistance.
Armin Arlelt discovers signs of an enemy presence and leads a group of soldiers to search for their hiding place. They uncover Reiner Braun hiding inside the Wall itself, but Levi Ackermann is unable to kill him before Reiner transforms into the Armored Titan. Outside the district, the Beast Titan appears along with a small army of Titans. It hurls a boulder into the breach in the Wall's inner gate, closing off the district's only remaining ground exit and trapping the Scout Regiment's horses on the Titan side of the Wall. This cuts off the Scout Regiment's only way of escape, forcing them to face the Titans.
Along the way, they stumble across a Titan, but it appears to be asleep and does not react to their presence. Hange Zoë speculates that it is not one of the new types that can move at night, but it could be inactive simply because they are traveling on a moonless night when the sun's light cannot reflect off the surface of the moon.
The Scouts leave the Titan alone and Eren Jaeger begins to feel the pressure of the operation, and how everyone is counting on him. Mikasa Ackermann and Armin Arlelt pick up on his nervousness. Though Eren denies his fear, Armin tries to comfort him by showing him that he is shaking as well. Most people would be afraid of Titans. Armin was almost eaten by one, but Eren was able to pull him out of a Titan's mouth. Armin asks Eren how he was able to do that.
Eren replies that he remembered when Armin showed him the book about the outside world and he realized that they were trapped by the Titans. He does not know why, but when it comes to taking back their freedom, he feels a strength flow through him. Feeling better, he thanks Armin and tells him that by this time next year he bets they will be looking at the sea.
Mikasa then stops, recognizing the woods they are in as the place she and Eren used to gather firewood. Ahead of them, one of the Scouts calls out that they have found a trail, and Eren, Mikasa, and Armin realize that they have finally come back to their hometown.
As day breaks, the Scouts charge on horseback for the Walls of Shiganshina District. When they get close, they switch to omni-directional mobility gear and scale the Wall. Erwin's plan involves sealing two gates; the inner and the outer of Shiganshina. This will isolate the town, allowing the Scouts to exterminate any Titans remaining inside. To avoid their enemies singling out Eren for an attack, all one hundred of the Scout Regiment soldiers are wearing hoods to cover their faces.
Eren is briefly overcome after landing on the Wall and seeing the town inside, but Levi Ackermann tells him to hurry, and he and his squad follow after their captain. However, Armin pauses, noticing a sooty residue on the top of the Wall; the remains of a fire. He flags Erwin's attention, realizing that Reiner Braun and Bertholdt Hoover must be nearby.
Around the outer Wall, Hange notices that there are no Titans around. She finds it strange, but Levi says they have to continue with the plan. Hange agrees and fires a green signal flare to announce that they have arrived at their destination.
Eren hurtles over the Wall and dives down to the breach below as he bites his hand to transform into a Titan. Nearby, inside unknown locations, Bertholdt and Reiner are able to see the light from Eren's transformation. Eren's attempt at hardening his Titan is successful in plugging the breach, and Mikasa retrieves him so he can rejoin the rest of their squad. Though his ODM gear is fine, he lost his cloak so Mikasa gives him hers.
The Scouts signal their success and Hange has them head for the inner gate, continuing to hide their faces. Eren cannot believe he plugged the outer gate so easily, but Levi warns him that their enemies can always break it again as long as they live. The operation will not end until they kill Reiner, Bertholdt, and any other enemies.
Erwin and Dirk look at the green flares signaling the sealing of the outer gate and Dirk remarks on how they have yet to see a single Titan. He wonders if their enemies were unprepared, but sounds doubtful. Before Erwin can fully reply, Armin arrives to elaborate on his discovery.
Armin found signs of someone camping. The pot was cold and lights were scattered on the ground below the Wall. From the cups, he could tell the campers were drinking something like black tea. Since there were three cups, there had to have been at least three people on top of the Wall.
Erwin is surprised by the cold pot because that means even though the Scouts had charged here at full speed on horseback, using ODM gear, the campers still had enough warning to hide that their pot could grow cold. By Erwin's estimates, the campers should not have had more than two minutes to react if they had spotted or heard the Scouts from atop the Wall, which is too soon for the pot to have already cooled.
Armin concludes that there must have been more than the three on the Wall. They must have had a scout as well. He realizes that the Scout Regiment should assume there could be many more enemies in hiding.
Recognizing Armin's gift for insight, Erwin has him take as many soldiers as he needs to locate their enemies. The gathered soldiers acknowledge their new directive and ask an increasingly uneasy Armin for his orders.
After Armin and his impromptu squad depart, Dirk notices that Eren's group is approaching. He asks if they should wait to seal the inner gate until they find the enemy, but Erwin says they will continue. The Scouts would lose a prolonged battle in enemy territory. Even if this is a part of their enemy's plan they will have to live with it. Besides, their enemy is not the only one hiding something.
Meanwhile, Armin agonizes over why their enemies have yet to show themselves and why the Scouts have been unable to find them. While hanging from the Wall, he glances up and remembers the Wall Titan in Stohess District. He fires a signal flare to recall the soldiers working with him and instructs them to tap down the Walls in search of potential spaces where a person can hide.
Hearing this and Armin's reasoning, Erwin fires a red signal flare to let Hange and Levi's squads know to halt the operation. Hange has the soldiers from the outer gate scatter and hold position as Erwin tells the soldiers around the inner gate to listen to Armin. Those at the inner gate split into two groups to search either side of the Wall.
As the search continues, Conny Springer wonders what the other soldiers are doing and Jean Kirschtein acknowledges that this is no longer a surprise attack. Nearby, Eren wonders if Armin figured something out.
Armin believes that if their enemies are keeping tabs on them and are able to watch everything that Eren is doing, it has to be from a place within the Wall, particularly if their enemies have no idea that the Scouts are aware of the Wall Titans. Without that knowledge, they would not expect the Scouts to consider an attack from within the Wall.
One Scout signals that he has found a cavity, but the Wall quickly opens to reveal Reiner Braun, who skewers the soldier with a blade. Reiner emerges from the opening only for Levi to dive down at him, slicing into his neck. With his other blade, Levi stabs into Reiner's torso as the two of them hurtle towards the ground. Surprised, Levi sees that Reiner is still alive. He pulls out the blade in Reiner's chest and halts his fall, letting Reiner hit ground alone. Levi wonders if it is another Titan power keeping Reiner alive.
Though grievously wounded, Reiner's body contorts and he transforms into the Armored Titan. Erwin calls out for the soldiers to look for Reiner's allies when the flash of a Titan transformation thunders behind him. He turns around and sees the Beast Titan and a small army of Pure Titans.
The Beast Titan hefts a boulder and throws it in a perfect arc at the Wall. It plugs the hole in the inner gate, preventing the Scout Regiment from bringing their horses through. With the horses trapped on the Titan side of the inner gate, their enemy will be able to take them out to prevent the Scout Regiment's escape and then annihilate the Scouts themselves.
Erwin remarks that this gives both sides what they want; a chance to settle everything once and for all.
Currently Publicly Available Information
Ore harvested from the Reiss family's underground cavern. Thought to be produced by some sort of Titan power. It emits more light than a torch, and with appropriate manufacturing, can greatly extend nighttime operations.