A NEET living in modern Japan dies suddenly due to his daily indolence and neglect of his own health. Instead of oblivion, he awakens as a newborn baby in a fantasy world where magic is real. He is reborn as Enid, the son of a village lord named Carla in the remote frontier town of Melia. He grows up surrounded by his beautiful mother, his big-breasted dark elf maid and nanny Ruina, and his attractive non-blood-related sister Amelia. Retaining the memories and knowledge of his past life, the young Enid discovers he possesses top-tier magical abilities, giving him a massive advantage in this new world.

As a teenager, Enid uses his modern knowledge and immense magical power to improve his daily life and surroundings. He invents items like soap and magical glasses, and eventually applies his understanding to spark an agricultural revolution in the new continent, causing the town of Melia to develop and prosper rapidly. During his adventures, he gains the power of the ultimate machine god named Shiru, which allows him to shift through time and space. This power sends him one thousand years into the future, from which he must use Shiru's power to safely return to his own time and his waiting family. Upon his return, armed with super-magical tools from a celestial city, he continues to drive Melia's growth.

With Melia flourishing and Enid having reached adulthood, the focus of the story shifts towards his personal life. To help find a suitable marriage partner for himself, he organizes a town party. This sparks a comedic battle for his affection, involving various women including his now-yandere-like sister Amelia. After twenty years in this world, Enid finally pursues marriage.

The narrative then escalates into larger-scale conflict. The Eads Empire launches an invasion with its magical army. After a year of fighting, Enid and the people of Melia successfully fight off the imperial forces and declare their nation's independence both domestically and abroad. However, the newly formed country immediately faces new threats. A mage named Marlene unseals a giant statue of the Goddess of Meria, which begins advancing on their land. Just as Melia finds itself in this desperate pinch, the goddess Shiru awakens at the perfect moment to turn the tide. Enid continues to pioneer not just the land, but the fate of his new country, using his unique blend of modern wisdom, powerful magic, and the bonds he has formed.