A certain young man was reincarnated as a young boy Leirus, as he is destined to defeat the demon king as the hero…. or not. Rather, he is put to work as a slave, waiting for death to take him from this world. Leirus who turned 15 was attacked by a chimera while being transported to a mine, and managed to escape through the confusion. However, without food, he was on the verge of starving to death, when he is suddenly brought back to life by a kind hearted girl Corona, the daughter of a dining hall. Leirus who manages to scrape by becomes an adventurer and finally experiences the kindness of people. However, the place he finds doesn’t last for long- The chimera’s shadow once again looms over him. In order to repay everyone who has helped him, Leirus has to stand up against his old foe!