In the year 202X, a race of otherworldly invaders attacked Earth with advanced technology and combat robots, and humans battled for 10 years just to survive. Park Sung Hyun was the leader of the troops in Incheon, Bupyeong, prior to these events. He had been a part-time worker at a convenience store like others before the invasion, but he became a skilled warrior in his quest to avenge his family. On the way to attack the Otherworlders’ headquarters, Park was trapped in a warp portal with the Otherworlders’ leader. When he woke up, he discovered himself in an unfamiliar fantasy world that reminded him of Europe during the Middle Ages, and his soul was trapped inside a weak blonde 15-year-old boy’s body.