In the first episode of "Ishura," viewers are transported to the city of Nagan Labyrinth, a place distinguished by its scholarship and the practice of "word magic," a magical discipline that allows its practitioners to manipulate their surroundings through verbal commands. However, this peaceful city harbors a hidden danger, as it is built around a vast, sentient labyrinth known for producing mechanical demons called golems, which disrupt the city's peace.

In this episode, we meet Yuno, a young word magician who is in love with her classmate Lucelles. Her peaceful life is shattered when the labyrinth awakens, unleashing chaos and leading to a brutal golem attack on Lucelles, who is dismembered in a shocking turn of events.

Amid the chaos, Yuno's attempts to repel the golems with her word magic prove futile until Soujirou the Willow-Sword, a mysterious figure from another realm, appears. Soujirou, notable for his casual attire and his sword—which effortlessly slices through golems—reveals himself to be a master of the Yagyu swordsmen of the Shinkage-Ryu from a distant world. His encounter with the labyrinth monster is an epic battle reminiscent of fights against giant monsters, where Soujirou employs his swordsmanship to strike the creature's vulnerable glowing blue spots.

The episode takes a moment to explain Soujirou's unique sword technique, albeit briefly, hinting at the complexity of his skills and teasing future revelations about his abilities. The climax of the battle is Soujirou's victory over the massive golem, leaving viewers eager to see how the series will escalate the challenges he faces in upcoming episodes.

By the end of the episode, Yuno and Soujirou, now allies, decide to travel together to Aureatia. Yuno wants to learn more about Soujirou and the looming conflict over the mantle of the True Demon King, while Soujirou shows interest in mastering word magic—and possibly in Yuno herself.