Before becoming the renowned captain of the Survey Corps, Levi endured a difficult existence in the Underground, a dumping ground in the capital. He headed his very own criminal enterprise, scraping by on meagre earnings thanks to his accomplices, Isabel Magnolia and Farlan Church. Without prospects, Levi makes a deal with Nicholas Lobov, an anti-expedition faction leader who pledges to offer the trio surface citizenship if they manage to assassinate a Survey Corps squad leader named Erwin Smith. When Levi and Erwin cross paths, the latter recognizes Levi's agility and prowess and offers him a choice: join the expedition team or face justice at the hands of the Military Police. As they get closer to the man they were sent to eliminate, the group devises a plan to save themselves from a bleak future in their former abode. Nevertheless, they soon realize that the outside world is not the haven they imagined and that freedom comes at a steep cost. Adapted from the eponymous manga spin-off, Shingeki no Kyojin: Kuinaki Sentaku explores the meeting of two critical Shingeki no Kyojin characters and the 23rd expedition's happenings beyond the walls.