A baby is born into a world of swords and magic, carrying the memories of his previous life in Japan. He is named Ars, and his new reality is harsh. He is the son of a poor farming family in a remote village, struggling with hunger and poverty in a fantasy realm where the royal family's power is in decline and turmoil is widespread.

Refusing to accept a life of constant deprivation, the young boy uses his unique situation to his advantage. He has a fondness for city-building games from his past life, and he discovers he has an affinity for earth magic. Using this magic, he begins to experiment, starting with simple gardening and land improvement to fill his empty stomach. His efforts evolve into more ambitious projects, such as selective breeding for better crops and constructing better housing. His most significant breakthrough comes when he successfully creates bricks.

By selling his high-quality bricks to a traveling peddler, Ars earns enough money to purchase a rare egg of a tamed beast, setting him on a new path of monster taming and nation-building. From these humble beginnings, his reputation begins to grow. His innovative use of magic and knowledge from his past life eventually leads the people to call him a Living God. The story follows his journey as he transforms his impoverished village into a thriving settlement and eventually founds his own nation.

The main character is Ars, a reincarnated boy whose past life knowledge and earth magic drive the entire plot. He is portrayed as pragmatic and inventive, constantly seeking ways to apply modern concepts like crop rotation and manufacturing to a medieval fantasy setting. The supporting cast includes his unnamed family, the local villagers, and the peddler who becomes his first business contact.

Notable narrative arcs include Ars's initial struggle to survive and develop basic agriculture using magic, his invention of bricks and the subsequent economic boom for his village, and the acquisition and raising of his tamed beast from a rare egg. As the story progresses, it shifts from pure survival to the larger-scale challenges of founding a nation, dealing with political turmoil, and managing the responsibilities of his legendary status.