Complete story — includes the ending
A few days earlier, Eren was informed by Erwin that Annie was suspected to be the Female Titan, thanks to Armin's deductions, and how they plan to capture her. In the present, Eren tries to transform but is unable to as his feelings for Annie are holding him back—he is unable to accept that someone he trusted turned out to be the Titan. He is then heavily injured from a tunnel collapse. Commander Nile Dawk of the Military Police Regiment demands an explanation from Erwin, holding him at gunpoint and threatening him of treason. As the Scouts try to capture Annie, Armin tells Eren that those who cannot sacrifice anything can never change anything; Mikasa reminds him that they live in a cruel world and must fight. Eren remembers his squad's deaths and his mother's, and uses his intense hatred of the Titans to finally transform.
Sources and content license
Source and revision history · Adapted from Wikipedia contributors, Attack on Titan season 1. Reference markers and HTML formatting removed. · Content license