The protagonist, Kouya, a reincarnated individual from Japan, finds himself in the world of Ampatri. He possesses several "gifts" from a goddess, including the ability to retain his memories, translate all languages, possess enhanced physical abilities, and immense magical power. Most notably, he has the "Network Connection" gift, which allows him to access the internet via smartphone and PC-type devices that manifest using his magic.
Upon arriving in Ampatri, Kouya finds himself in a medieval European-style city. He attempts to buy a skewer of grilled meat at a street stall, offering a gold coin. To his shock, the vendor informs him that the skewer costs 120 Gold (G), and his gold coin is only worth 1 G. He quickly realizes his initial 100 gold coins are equivalent to a mere 100 Japanese Yen, leaving him with very little spending money.
Desperate, Kouya uses his "Network Connection" to search for ways to exchange his gold. He discovers a website called "Mithril Plaza" that buys precious metals. He tentatively uses their service, sending a gold coin through a magically appearing box. To his astonishment, he receives an email confirming the purchase and a deposit of 15,000 Yen into his old Japanese bank account. However, this realization is short-lived as he remembers he is in another world and Japanese Yen is useless there.
He then stumbles upon an online shopping site, "Mitsurin," and discovers it delivers to Ampatri for "Platinum members" and above. Having recently become a Platinum member, he decides to test it. He upgrades to "Mithril membership" for an annual fee of 10,000 Yen, which promises instant delivery. He orders a multi-tool, which promptly appears in a box. He realizes he can now use his Japanese Yen to buy goods in this world. He then decides to buy items that might sell well locally. Considering the medieval setting, he purchases 5kg of high-quality Japanese salt from Mitsurin for 2,500 Yen.
While carrying the salt, Kouya bumps into a young man named Almehi Faleno, who introduces himself as Al. Al, who runs a trading company, notices the salt and offers to buy it, mentioning a current shortage and high demand. Kouya agrees, and they head to Al's large trading company headquarters. Al is incredibly impressed by the salt's purity and offers to buy all 5kg for 50,000 G. Kouya, calculating that this would equate to a massive sum if converted back to Yen, readily accepts. However, Al pays him with five "Holy Silver Coins" instead of the expected gold.
Confused and feeling cheated, Kouya uses "Mithril Plaza" again to appraise the silver coins. To his utter shock, the coins are revealed to be made of "Mithril," a metal not found on Earth, and are valued at 200 million Yen each, totaling 1 billion Yen. He realizes he has made an enormous profit.
With his newfound wealth, Kouya decides to buy more salt (20kg this time) and sells it to Al for 200,000 G, securing his immediate local currency needs. He also learns that Al's company is well-regarded.
After a week, Kouya has accumulated a significant amount of local currency (around 30 million G). He decides to buy a slave to help with transporting goods. Al recommends a slave merchant, and Kouya, with a budget of 300,000 G, purchases a frail, injured 13-year-old girl named Fina. He immediately treats her wounds using medical supplies bought from Mitsurin. He discovers that a special ointment causes her wounds to heal miraculously fast.
After treating Fina, Kouya introduces himself and learns her name. He then provides her with nutrient-rich jelly drinks from Mitsurin, which she devours with great enjoyment, feeling a surge of strength. Kouya assigns her the role of a general helper, acknowledging her small stature makes heavy labor difficult.
Another week passes, and Fina has transformed. Her health has improved dramatically, and she now possesses surprising strength, easily pulling a cart laden with goods. She attributes this to the nutrient drinks. Kouya, impressed by her strength and the efficiency it brings to their business, continues to trade with Al, expanding their product range beyond salt to include spices like pepper. Al warns Kouya that other merchants are becoming suspicious of his sudden success. Al also suggests Kouya join the Merchants' Guild, given the scale of his operations, to avoid future problems. Kouya, considering buying a house to use as a base of operations, decides to consider the guild membership.