The previous episode ended with Eren's stubbornness to save his victorious homeland before Zeke's salvation to sacrifice Eldia for the greater good. With a single command, thousands of colossal Titans emerge from the walls that have protected Pradis for centuries. As you read this article, these Wall Titans are marching across the sea with the sole purpose of abolishing the outside world. Can Mikasa, Armin and the remaining members of the 104th Training Corps let humanity perish to save their homeland? We'll find out in Attack on Attack on Titan Season 4 Episode 22.
With the activation of the rumble, Reiner's worst nightmare has become reality. The people he wants to protect will be trampled by the Wall Titan army. Thus, the only way out is to kill Eren for the greater good of the world. However, easier said than done. The founding Titan is colossal even compared to the colossal Titans, so it is almost impossible to locate Eren's neck.