The episode begins with a flashback to a young Leonis Shealto in a fortified city near the border of the Kingdom of Rognas. He is confronted by Arakael Degradios, who suggests annihilating the city's inhabitants and the monsters for the greater good. Leonis refuses, stating that he cannot condone such an act.

In the present, the officers in the garden of the Seventh Assault discuss a mysterious phenomenon. Elfiné Phillet, a holy swordswoman, reports her findings, which hint at the existence of voids in the underground areas of the city. Despite initial skepticism, the evidence grows that a void is moving through the city's maintenance tunnels and may be targeting the power plant.

Meanwhile, Selia and Leo are at the Sunny Spot House, a restaurant and orphanage. They chat with the children, and Selia is asked to show her Holy Sword. Leo decides to entertain the kids with a demonstration of his magical abilities. At that moment, the city is attacked by the voids, triggering a massive onslaught known as a Stampede.

The Seventh Assault Garden switches to fortress mode, and the entire military prepares for the Stampede. Selia and Leo join the battle. Selia takes on the role of protecting Leo as he prepares to cast a powerful spell. Leo, however, recalls his past life and decides he cannot ignore those who threaten him and his servant.

Leo successfully casts a 10th-tier spell and defeats a massive void. Just as they believe the battle is over, Arakael Degradios appears and recognizes Leo as Leonis. The episode ends comically as Leo finds a button supposedly capable of transforming the city and contemplates whether to press it.