After sacrificing himself to save a stranger, a 34-year-old NEET is reborn in a magical realm as Rudeus Greyrat, starting anew as a baby with memories of his past intact. Determined to live differently, Rudeus strives to avoid past errors and embrace a purposeful existence. Endowed with extraordinary magical abilities and the wisdom of an adult, Rudeus impresses his adoptive parents with his potential brilliance. Under the tutelage of formidable mentors like his swordsman dad and the mage Roxy Migurdia, he refines his skills. Despite his façade of innocence, Rudeus, a former otaku, leverages his knowledge to romantically pursue women beyond his reach in his previous life.