A 34-year-old NEET loses his life saving a stranger in a traffic accident, only to wake up to find himself reborn as the baby Rudeus Greyrat in a new world filled with magic. The child of the adventurers Paul and Zenith Greyrat, his innate talent for magic is immediately recognized when he turns two, and the magic tutor Roxy Migurdia is brought to his home to refine him into a mage. With a tremendous amount of magical power and a wealth of knowledge from his original world, Rudeus seeks to fulfill his only desires from his previous life—to not repeat the mistakes of his past and die with no regrets.