In the year 202X, otherworlders invaded earth. The otherworlders, having more advanced technology, hunted down humans with combat robots and viral weapons. The remaining humans battled on for 10 years just to survive. The main character, ‘Park Sung Hyun’, was the leader of the troops in Incheon, Bupyeong. Prior to the invasion of the otherworlders, he had been an ordinary part-timer at a convenience store, but he became a strong warrior after losing his family, fighting to avenge them. During an attack on the headquarters of the otherworlders, Park Hyun Sung was trapped in a warp portal with the leader. When he awoke, he found himself in a fantasy world that reminded him of medieval Europe, and his soul was trapped inside the body of a weak blond 15-year-old pretty boy. Hyun Sung was surprised by the unfamiliar surroundings and his weak body, but found out that he is occupying the body of Ian Albarren. He also found out that his father is a lord of a land who owes a large debt to the great lord and faces a difficult time ruling over his land. Park Hyun Sung, who had been fighting combat robots and viral weaponry from otherworlders with advanced technology, decided to get used to this fantasy world and fight against monsters instead.