Narrowly avoiding execution, Eren's fate is entrusted to the Scout Regiment where he must prove capable of following orders. But on an expedition outside the wall, a unique female Titan appears and cuts through the Scouts, leaving a trail of carnage and splintered bones behind her and making it difficult for Eren to control his rage. As it becomes obvious that a traitor is sabotaging the Regiment from within, Eren must ask himself who humanity's true enemy really is. Includes extras.