Just when an unemployed thirty-four-year-old NEET reaches a dead end in life and decides that it's time to turn over a new leaf—he gets run over by a truck and dies! Shockingly, he finds himself reborn into an infant's body in a strange new world of swords and magic.

His new identity is Rudeus Grayrat, but he still retains the memories of his previous life. Follow Rudeus from infancy to adulthood, as he struggles to redeem himself in a wondrous yet dangerous world.