Yuuji Sano, a black company employee, is summoned to another world while finishing his work at home. His profession in the other world, a Monster Tamer, is considered a job that makes it difficult to become an adventurer. However, thanks to some slimes he met, which read several magical books, he gained magical powers and a second profession, Sage. Yuuji acquired overwhelming power, but is he conscious of his strength? Blindly becoming unparalleled and strongest in the world!

One day, high school student Michio Kaga attempts to start a strange online game he found while browsing the internet. Instead, he gets transported to a rural village in the game's world, equipped with special skills and an overpowered sword. After collecting his thoughts, he finds himself battling against bandits and soon realizes that he cannot log out. Resigning himself to fate and accepting this reality, Michio sets out on a journey—enjoying his new life, conquering dungeons to earn money, and building a harem to satisfy all his manly desires.

One day, high school student Michio Kaga attempts to start a strange online game he found while browsing the internet. Instead, he gets transported to a rural village in the game's world, equipped with special skills and an overpowered sword. After collecting his thoughts, he finds himself battling against bandits and soon realizes that he cannot log out. Resigning himself to fate and accepting this reality, Michio sets out on a journey—enjoying his new life, conquering dungeons to earn money, and building a harem to satisfy all his manly desires.

To prepare for reincarnation in another world, Kelvin gives up select memories from his previous life in exchange for powerful abilities, additional skill points, and an S-class summoner title. As a bonus, the goddess facilitating his rebirth, Melfina, offers him a choice of any companion to give him a head start in his summoner role. Kelvin—who has fallen head over heels for Melfina at first sight—promptly chooses the deity, confident that his passionate feelings for her will resurface even without all of his memories. Kelvin embarks on his exciting new journey with Melfina as his guide. However, in order to summon his beloved goddess' physical form, he needs to acquire significant amounts of mana points—and the best way to accomplish this is to level up by fighting strong enemies and making contracts with even stronger companions.