Levi Ackerman, grappling with the aftermath of the Rumbling, has become even more cold, distant, and sharp-tongued. His once formidable demeanor has hardened as he struggles to find purpose after losing all his closest friends in the war.

Seeking a new path in life, he opens a boxing gym where he teaches self-defense classes. It's here that he meets a quiet, timid, and slender young woman who seeks to learn self-defense.

Unbeknownst to Levi, she harbors a dark secret: she is a victim of domestic abuse at the hands of her father, and she yearns to empower herself by learning to defend against him.