The protagonist, a young man named Daiki Kotori, is abruptly transported from his everyday life in Japan to a grand, opulent hall in the Kingdom of Naihead. He finds himself alongside three high school students: a flashy boy named Takumi, a physically imposing boy named Aoi, and a nervous girl named Mirai. They are informed by King Miharu and his armored knight that Naihead is under invasion by a Demon Lord, and they have been summoned by a goddess to aid in the fight.
Initially bewildered and skeptical, the summoned individuals are tested by the knight using a metallic plate that reveals their latent abilities. Takumi is identified as a potential hero with four combat skills, including swordsmanship and fire magic. Aoi displays skills suited for a guardian, excelling in shield and earth magic. Mirai possesses support-oriented magic, with high-level light, water, wind, and staff skills. Daiki, however, is revealed to have only one skill: "Teleportation Lv. 1." The knight deems him useless, and he is dismissed with some gold coins to await the heroes' success.
Daiki is then escorted to a modest room and meets the Prime Minister, Yanskill Rudbook. The Prime Minister, intrigued by Daiki's foreign possessions, proposes a trade: Daiki's modern wristwatch in exchange for personal support. Daiki agrees, and the Prime Minister is captivated by the watch. He also shows interest in Daiki's smartphone, but its functionality is limited without power, making it less valuable. The Prime Minister generously provides Daiki with 300 gold coins, significantly more than the initial offer.
Later, Daiki encounters a mysterious, young-looking girl named Mira, who claims to be a servant of the main god, Calamityl. She reveals that she summoned Daiki and, despite his initial confusion and the pain it causes, enhances his Teleportation skill, adding new functions. She then departs, leaving Daiki with two "Skill Orbs" containing "Swordsmanship Lv. 1."
Daiki, now with a substantial amount of gold, decides to explore the city. He learns about the existence of an Adventurer's Guild and the concept of slavery. He attends a slave auction, where he witnesses the sale of various individuals, including a winged beastman, a beautiful woman, and several others. He becomes fixated on a young noble girl named Yufi-lit, who was formerly a noble from the fallen Mugdam Kingdom. Despite his initial intention to hire a bodyguard, Daiki impulsively bids on Yufi-lit, spending almost all his gold. He purchases her for 290 gold coins, a price that surprises even the auctioneer.
After the transaction, Daiki learns about the slave contract, which involves a magical mark placed on Yufi-lit using his blood. He also discovers the existence of healing potions and a "contraception magic." He returns to his inn with Yufi-lit, who is initially hesitant and fearful but gradually opens up to Daiki. He explains his situation as an otherworldly summoned individual, which Yufi-lit accepts, especially after learning about the "Hero Summoning" rumors.
Daiki discovers that his Teleportation skill has a limited range and a cooldown period, making it less useful than he initially hoped. He also learns that Yufi-lit's "Swordsmanship Lv. 1" skill has been enhanced to Lv. 2, implying his ability to transfer skills to others. He decides to visit the Adventurer's Guild with Yufi-lit to find work and acquire necessary equipment. At the guild, they register and accept a quest to gather herbs and hunt small monsters in a nearby forest. Daiki also learns about the existence of magic items and the social hierarchy of the world. He buys Yufi-lit a bronze sword and leather armor for a few silver coins. As they head towards the forest, Daiki realizes the vastness of the kingdom and the agricultural nature of the surrounding lands. He also learns about Yufi-lit's noble upbringing and her family's history as royal swordsmen.
