Raphtalia, a demi-human girl, was living happily with her family and friends. However, she loses her parents to a monster that appeared during a phenomenon called the "Waves of Calamity". Her village that was on the brink of destruction then got plundered by soldiers who came to her village and turned her into a slave. However, her fate made a drastic turn when she meets Naofumi Iwatani, a hero summoned from another world to save this world. The bond between the two gradually deepen as they live together while fighting the monsters from the "Waves of Calamity". A retelling of the main story in the perspective of Raphtalia.