Johan Anderson, a high school teenager in Japan, along with his classmates, is suddenly summoned to another world by an empire that needs a hero to win the war. Each student gets a job that determines their abilities, but Johan gets a job that seems strange and useless: 'Modern Soldier'.
After the war ended, the relationship between Johan and Yumi became blurred, like a fog obscuring their understanding of each other. Johan's cold actions toward his classmates, the people from his own homeland, created a distance between them. Although Yumi remained loyal to supporting Johan, she couldn't shake the skepticism that gnawed at her mind every time Johan showed indifference toward the people he was supposed to protect—the very people who once shared school days with him.
However, it wasn't that Johan failed to understand their feelings. Instead, it was Yumi who had to learn to grasp the reasons behind Johan's actions. The war had forced Johan to change, and while it was heavy on his heart to take someone's life, he was still human—still a teenager burdened with immense responsibility. Every life he took left a deep mark on his mind, especially at night, when the war was over and the silence replaced the roar of battle.