Attack on Titan: Short Stories is the first collection of short stories for the Attack on Titan manga, written by Hajime Isayama. The booklet was included in the special edition of volume 20.
The English version was exclusively included in the season 3 part 1 manga box set released by Kodansha USA in October 2018.
The stories were originally published on the "au Smart Pass" and "Sugotoku" apps.
Plot: As the rain pours down in a walled-off world, the soldiers go about their daily lives, but are haunted by visions in the nighttime. What goes on in Levi's mind when the weight of the world lies on his shoulders? What words do Annie and Ymir exchange during training?
Summary: The booklet contains two stories: "Shelter from the Rain" and "Goodnight, Dear and Sweet Dreams". Moblit attempts to take cover from the rain in a store after running errands, where, to his surprise, he finds Levi. Levi is there because Erwin summoned him to meet up with him.
Source: Attack on Titan: Short Stories, available under CC BY-SA 3.0.