The narrative begins with Ex Hailwood, a fifteen-year-old heir to the prestigious Hailwood Marquisate, being summoned to his father's study. He is met by his stepmother, his younger brother, three knights, and the butler. His stepmother, who is also the current acting head of the household and holds significant power due to her lineage and her late husband's passing, informs Ex that he is to be disinherited and expelled from the family that very day. Ex, having anticipated this possibility after his father's death and his own subsequent physical incapacitation, questions the legality and the need for such a drastic measure, especially the expulsion. His stepmother remains silent, while his brother mocks him.
The reason for Ex's disinheritance is revealed to be his lack of swordsmanship talent. The Hailwood family is a renowned martial lineage, with a history of producing skilled swordsmen and even royal sword instructors. Ex, once hailed as a prodigy, suffered a debilitating physical condition after his father's death at age ten, which, while not preventing daily life, made him incapable of becoming a top-tier swordsman. His younger brother, however, excels in swordsmanship, making him the preferred heir in the eyes of their stepmother and the family's martial tradition. Ex argues that he has contributed to the marquisate through his administrative reforms, improving the territory's prosperity and the lives of its citizens, but his efforts are dismissed as mere "chores" by his stepmother and brother, who prioritize martial prowess above all else. Despite his pleas and his efforts in managing the territory, Ex is given a severance package and forced to leave.
Outside the study, loyal retainers express their concern. Ex, now a commoner, advises them to remain silent to avoid repercussions from his stepmother. He plans to head to the capital to find work as a merchant, leveraging his literacy and calculation skills. He sells his noble attire for more practical clothing and purchases a sword for self-defense.
While traveling, Ex has a vivid dream where he encounters a being who identifies herself as a "God of Destruction and Creation," referred to as a "Destruction God" by humans. This deity, who appears as a young girl, claims to have chosen Ex and bestows upon him a portion of her divine authority, the nature of which is unclear to Ex. He awakens in a humble inn, dismissing the dream as a result of his recent trauma.
The next morning, Ex joins a merchant caravan heading to the capital. During the journey, he encounters a young demon girl named Lucia and her older sister, Arsia, who are being transported as slaves. Ex, witnessing their plight and recognizing a shared sense of injustice, feels compelled to help them. Their caravan is ambushed by bandits, including a powerful mage. While most merchants and even the hired adventurers flee, Ex, driven by a newfound ability to move his body with unprecedented agility and precision, single-handedly defeats the bandits. He discovers that his physical limitations have vanished, and his swordsmanship has become extraordinary. He also realizes he can mentally "break" objects, a power he uses to free Arsia and Lucia from their shackles.
The caravan is then confronted by two terrifying Dragon Zombies, controlled by the same mage who led the bandits. The mage, revealed to be an assassin, reveals that Ex's stepmother may have orchestrated his expulsion and the zombie attack. Ex, now possessing incredible combat prowess, defeats the Dragon Zombies and apprehends the mage and his accomplices. He learns that the Dragon Zombies were a tool to eliminate him, and the assassins were hired by his own family.
The merchant caravan, grateful for Ex's intervention, agrees to help him and the demon sisters. Ex uses his newfound abilities and the bounty from defeating the Dragon Zombies to purchase the freedom of Arsia and Lucia, and learns that their parents were sold separately to a wealthy merchant in the capital. He decides to become an adventurer to earn enough money to reunite the family. The narrative concludes with Ex, Arsia, and Lucia arriving at the capital, where Ex registers as an adventurer, ready to face his future and uncover the truth behind his family's betrayal.
