Forest of Giant Trees: The 57th Exterior Scouting Mission, Part 2 (巨大樹の森 ―第57回壁外調査②― Kyodaiju no Mori -Dai Gojū-Nana Kai Hekigai Chōsa (2)-?) is the 18th episode of the 1st season and the 18th episode overall of the Attack on Titan anime, produced by Wit Studio and Production I.G.
After their encounter with the Female Titan, Reiner tends to Armin's wounds while Jean calls for his horse. With the situation looking bleak as they have to decide who will be left behind, Christa appears with two horses, saving everyone. Meanwhile, the Female Titan keeps running towards Eren's location, killing anyone who gets in its way. Much to the surprise of the soldiers, the formation heads into a Forest of Giant Trees. Erwin orders that only middle section is to enter the forest while all other soldiers go around, eventually stationing themselves near the trees. They are ordered to kill any Titan that attempts to enter the forest. The lower ranking soldiers wonder about this decision, but knowing that Erwin must have a reason for it, they decide to obey their orders. The Female Titan then enters the forest, chasing Eren, while the rest of the squad ask Levi for orders, proposing to engage in a fight with the pursuer.
After the Female Titan leaves for Eren, Reiner asks Armin about his omni-directional mobility gear while tending his wounds. Armin replies that it seems to be working properly. Reiner then notes that they have only one horse, with Jean attempting to call his own. He thinks to himself about what they will do, knowing that someone will have to be left behind. Meanwhile, Armin seems to be spacing out, remembering his encounter with the Female Titan. Reiner then also says that they have to decide the one who will stay behind. Jean fires an emergency signal as a last hope and Armin proposes himself to be the one left behind and as is about to ask Reiner to deliver a message to Erwin, when Jean notices someone approaching.
They see Christa running towards them, leading two horses, one of them being Jean's horse. Reiner notes that Christa is a really nice person, unable to believe that the emergency signal actually worked. Christa notes that she is glad they are all alive as the three boys stare in awe, with Reiner even stating to himself that he wants to marry her. Afterwards, head back to the formation, thinking that a retreat signal should be given soon. But, they are surprised to find out that the mission continues with different course. They question this decision, but follow the order and fire the green signal as well.
Elsewhere, Levi and the rest of his squad see this too, with Oruo being the one to shoot the signal. Just as Eren thinks to himself that the operation seems to be going well, a soldier approaches them with a verbal message that the right side of the formation has been destroyed. Levi orders Petra to deliver this message further to the formation, with Eren wondering if Armin and the rest of his team mates are okay. At that moment, a signal of an Abnormal Titan appears.
At that location, four soldiers engage in combat with the Female Titan. Darius Baer Walbrunn shoots a black smoke signal towards it, stopping it in its running. He then orders the rest of the soldiers to attack, thinking that their target cannot dodge three simultaneous strikes. However, the Female Titan jumps and crushes two soldiers, one against a building and one on the ground, with the third one being killed by the Female Titan spinning him on his wire so fast the inertia breaks his spine and folds him. Dhalis tries to escape in order to warn everyone of this Titan, but it catches up with him and kills him by kicking him and his horse into the air. Two more soldiers notice this and head towards the female in an attempt to stop it, just to lead to more casualties.
Meanwhile, the formation keeps heading east, contrary to the original plan. They eventually reach a Forest of Giant Trees. As Erwin goes into the forest, he orders that only the center of the formation should enter it. Sasha questions their course, but is told that they're going around the forest. Elsewhere, Jean also wonders about the plan as it is completely changed compared to their original mission. A senior soldier then orders them to stop and get rid of any Titans that attempt to enter the forest. At that time, Conny also asks about what happened to the formation, with Mikasa replying that they're most likely avoiding the forest this way, losing their recon ability in process.
Waiting above the trees, Jean complains about the orders yet again. When Armin asks him about his intentions, he replies that he is going to follow the orders, that being the right decision. As they see a Titan approaching, Armin wonders about Erwin's hidden motive. Inside the forest, Eren asks Levi why they would enter the forest alone and lose their ability to protect themselves. Levi replies that if he does not want to die he should think, noting the trees to be the perfect environment for omni-directional mobility gear. Eren figures out that he will not get every answer on a silver plate, thinking that others learned to fight this way as well, but he then notices that the others have no idea about what is going on either.
While Armin deduces that Erwin intends to deal with the Female Titan inside the forest, a horrified Jean watches all the Titans attempting to reach them, noting that they do not need to fight as long as they do not try to enter the forest. Suddenly, a black smoke signal is shot right behind Eren's group, signalling the arrival of an Abnormal. Eld deduces that it is the one that has been crushing the soldiers at the right side. Levi orders everyone to draw their blades just as they watch a soldier appear. Moments later the Female Titan bursts through the trees and swats the soldier behind them, beginning the chase.
As they are being chased, Petra asks for a permission to use omni-directional mobility gear, but Levi silently watches as reinforcements arrive to engage a fight with the Female. However, they are easily killed, much to Eren's horror. Petra asks Levi for orders yet again, while Oruo suggests taking the Titan down. Eld takes out his blade, determined to kill it. Eren smirks, thinking that the Female has chosen hell for chasing these master Titan killers. Eren is then surprised to see that Levi is still being silent and looking forward. After much panic from the squad, Levi finally speaks and tells them to cover their ears, taking out his signal flare and firing it upward.