After being hounded, humiliated, and tormented his whole life, a 34-year-old shut-in had the resolve to do something heroic—only for it to end in a terrible disaster. However, fate has it that he awakens as Rudeus Greyrat in another dimension, beginning his life as a kid born to two loving parents. Rudeus quickly adapts to his new surroundings by preserving memories and competence from his previous existence. He begins to display magical power that surpasses all expectations, refining his technique with the help of a wizard named Roxy Migurdia. Rudeus' father, Paul, teaches him swordplay, and he meets Sylphiette, a little girl who quickly becomes his greatest friend.