After the Warriors' attack on Shiganshina District, Annie Leonhart joins the 104th Cadet Corps under secret orders. When the time comes for graduation, she participates in the Struggle for Trost. After graduating from her Cadet Corps, she joins the Military Police Regiment while her Warrior comrades Reiner Braun and Bertholdt Hoover join with the Scout Regiment.
While Annie is trying to escape from Stohess District transformed in her Titan form, she has memories about her father. They are in front of a cabin, surrounded by trees, and several punching bags can be seen. Her father apologizes to her, saying that it is too late to ask for forgiveness. However, Mr. Leonhart tells her something: even if the whole world hates her and treats her like an enemy, he will always be by her side. He then tells her one last thing: to promise him that she will come back.
This memory triggers her hardening ability, encasing her into a crystal cocoon and allowing her to avoid interrogation, although she is captured and placed underground.
Shortly before the Battle of Shiganshina District, Bertholdt remembers back to the Struggle for Trost, where Reiner had pressured Annie to take off Marco Bodt's Omni-directional mobility gear, to prove that she and her father were different from the "evil race" within the Walls.
Before the curtain's rise at Willy Tybur's production in Liberio, Mr. Leonhart speaks with Karina Braun, the latter praising Annie for having devoted her life to Marley. Mr. Leonhart refuses this, adamantly stating that she is alive, because she had promised to come home.