Ardys, a user of 'Sword Magic', is a mercenary who takes on various requests such as slaying monsters, guarding, and investigating, depending on the reward. On his way back from an investigation, he encounters and protects twin girls who are the sole survivors of a caravan attacked by bandits. In this world, twins are considered 'cursed children' and are shunned. Despite the world's prejudice and the enmity towards the goddess revered worldwide, Ardys carves his path with his sword. This is the story of the 'Swordsman' known as the 'Master of a Thousand Swords'.