In Stohess District on eastern Wall Sina, Annie prepares to join her Military Police in a mission to escort Eren to the capital until she is pulled aside by Armin, who asks for her assistance in sneaking Eren away to safety. Hesitantly agreeing, Annie is led by Eren, Armin, and Mikasa to a tunnel leading underground.
Annie refuses to follow the Scouts below, and their suspicions that Annie is the Female Titan are confirmed. Escaping capture, Annie transforms in the middle of the city.
You can watch Attack On Titan Episode 23: Smile: Assault on Stohess, Part 1 online for free in the next link: