When two men attack the base and inject a poison in Hanji leaving her sick for weeks, Levi, Eren, Mikasa, and Armin go to the underground city to find the man who ordered the other two to kill Hanji and Levi. In the underground, Levi sees many things that he recognizes and begans to feel his heart longing for his two friends once again. But once he stops paying attention to the things around him, he is knocked out and taken hostage. And to think this all started because of a puppy named Jase.