In order to revive humanity's dwindling hope, the Survey Corps sets out on a mission to reclaim Wall Maria, where the war against the cruel "Titans" resumes. Eren Yeager and the Corps return to the ragged Shiganshina District, which was formerly his home, and find the area strangely devoid of Titans. Even after plugging the outside gate, they face no resistance. The operation goes smoothly until Armin Arlert, who is suspicious of the enemy's absence, uncovers troubling clues of a possible plot against them.