|Look around you. These overgrown trees are the perfect environment for vertical maneuvering equipment. Now think. Use the modest intellect you do possess. Think hard. Your life depends on it.|
|— Captain Levi informs Eren of a key strategy|
Jean Kirstein, Reiner Braun and Armin Arlert are recovering from their battle against the Female Titan. They treat their wounds and look for their horses. Finally Krista Lenz appears with their horses and they start riding while following the formation.
Meanwhile, the Female Titan keeps killing soldiers and advancing towards the center of the formation. Erwin decides to enter inside the Titan Forest, making the Special Operations Squad enter too and the rest of the soldiers guard outside the forest. However, Squad Levi gets a horrible surprise when the Female Titan enters at the forest too, following them at close distance.
Still trying to recover from their encounter with the Female Titan, Jean is trying to call his horse while Reiner tends to Armin's head wound. Not wanting to stay exposed and vulnerable to attack, Jean worries that someone may have to be left behind if his horse does not return. Armin, in deep thought, remembers the Titan crouching over him and focuses on her face. He snaps out of it when Reiner calls out to him.
Reiner comes to the same conclusion as Jean and suggests that someone will have to be left behind. Armin wants to try one more thing before they do it. He tells them that the formation is still headed in the same direction; if they fire a signal flare another group could still be close enough by to help them out. After waiting a few minutes with no response, Armin volunteers himself to stay behind on the condition that the others relay a message to Commander Erwin personally. Fortunately, before Armin can continue, Krista Lenz, after seeing the signal, arrives with Jean's horse. She found it after it was frightened away by the Titan. Everyone expresses their gratitude and they are on their way. Riding along, they see a series of green smoke signals. The formation is not retreating, only changing course. They wonder if the information about the right flank has reached Commander Erwin. At the moment however, the only thing they can do is change course with everyone else.
Traveling with the Special Operations Squad, Eren finds it odd that they have not come upon any Titans before realizing that it is because of his position in the formation. At that thought, he wonders if there have been any victims on the front lines. A messenger arrives and tells the squad about the chaos in the right flank. Captain Levi orders Petra to relay the message to the group on their left. Hearing the news, Eren is concerned about Armin. Shortly afterwards, they see a black smoke signal, indicating an Abnormal Titan has broken through the lines.
The Female Titan is making her way towards Eren and taking out anyone who gets in her way. A small group confronts her in an attempt to finally stop her charge. They launch an attack from all sides, but she jumps into the air, dragging the soldiers with her. As she lands, she crushes one, kicks another into a building and then swings another around by his vertical maneuvering equipment until the force breaks his back, folding him in half. She runs the remaining member down and kicks him through the air before continuing her search.
Word about the right flank is still only halfway through formation. Seeing that they are heading in the wrong direction, a few groups wonder why there has not been a course correction. In the distance they see the Titan Forest. Reaching the entrance of the forest, Commander Erwin tells his subordinates to relay the message that only the central column will be going through; the flanks will travel around. Now traveling on the path in the forest, Eren states the obvious about the formation losing its ability to detect Titans early. He also expresses concern about being able to protect the convoy of carts along. Annoyed, Levi tells him to look around. Being surrounded by the trees lets them use their vertical maneuvering equipment to its fullest potential. Not wanting to answer any more of Eren's questions, Levi tells him to think before he speaks. Noticing the worry on the faces of his squad he realizes that they do not know what is going on either. The group is interrupted by the sound of something behind them. Levi tells his group to get their weapons ready. Smashing her way through another group of soldiers, the Female Titan enters the forest.
Current Publicly Available Information
12. The Titan Forest
There are forests of giant trees both inside and outside the Wall. They grow wild along the borders of one district, averaging a height of over 80 meters. No one knows why trees of this size exist, but some have proposed the nature of the soil as the cause. Before the fall of Wall Maria, people maintained the forest as a tourist attraction. Without human intercession in the last several years, the area has fallen into ruin, with the forest path mostly swallowed up by weeds and trees, although parts of the path remain intact from the comings and goings of the Titans through the woods. The forest has become an important base for the Survey Corps, used to protect themselves from the Titans while on expeditions outside the Wall.
Author's note: (With thanks to Ukyō Kodachi and Kiyomune Miwa.)