17. Female Titan - The 57th Exterior Scouting Mission (1)

Complete story — includes the ending

As they begin the 57th Expedition, the Scout Regiment assembles into their Long-Range Scouting Formation, wherein they spread out in a semicircle around the main wagon train and signal by colored flare guns if Titans are nearby so the group can collectively alter course to avoid conflict if possible. Things get difficult when a Female Titan suddenly appears at high speed toward Armin's squad. Much to Armin's shock, this Titan is intelligent enough to kill his seniors and protect her neck. She captures Armin, but after seeing his face, inexplicably lets him go, causing Armin to realize that she is possibly a human with a Titan form like Eren. Armin is picked up by Reiner and Jean, who reveal that their right flank was wiped out by Titans. They realize that the Female Titan's target is Eren and try to stop her but fail.