The protagonist, Okura Heihachi, is a devoted player of the popular mobile game "Girls Corps" (GC), a mid-evil European-themed gacha game where players collect and train female warriors. He is struggling with the game's gacha system, having spent a significant amount of money. A new UR character, Luna Valad, a vampire loli, has been released, and Heihachi is desperate to obtain her. He waits for midnight, believing it increases his chances, a superstition he calls the "0 o'clock religion."
After a 11-pull gacha, which costs 5000 yen, he obtains a UR item: "Invitation to Another World." This item is unknown to the game's community, leading Heihachi to believe he is the only one to have acquired it. Upon using the item, his smartphone emits a blinding light, and he finds himself transported to a savanna-like landscape, still in his pajamas and barefoot. He initially believes it's a dream but quickly realizes it's real when he feels pain.
He encounters a purple, bipedal goblin-like creature and narrowly escapes by climbing a tree. He deduces that the "Invitation to Another World" item from GC is responsible for his transmigration. His smartphone, now only displaying the GC interface, shows his player level has reset to 1, and his username has changed to Okura Heihachi. All his in-game units and items are gone, except for a single unit: himself, represented by his face as an icon. He also finds 50 magic stones, the in-game currency for gacha pulls.
He performs another 11-pull gacha, which guarantees a UR unit. He obtains an SSR "Book of Languages" and a UR unit named Noru Fanya, a silver-haired knight with a distinctive helm. The "Book of Languages" materializes into a physical book, allowing him to understand the world's language. Noru Fanya, a powerful UR unit, is summoned and immediately falls from the tree Heihachi is in, due to his forgetfulness. Heihachi apologizes for the rough summoning, and Noru Fanya, despite her initial distress, accepts his apology and reveals she was summoned to assist him. She explains that summoned individuals gain some of the summoner's knowledge and memories.
They learn that the world runs on magic energy (maso) and that monsters drop items upon defeat, much like in GC. Heihachi's smartphone is powered by maso. They also discover that the GC gacha has changed, now only offering UR units and new items like the "Camp Set" and "Book of Languages." Noru Fanya's summoning cost prevents further summons for now. Heihachi, now designated as the "Commander" unit with a buff ability, and Noru Fanya decide to become adventurers to earn money and gather information.
They participate in a goblin hunt, where Heihachi, equipped with an SR "Excalibur" and an SR "Pot Lid," surprisingly defeats the remaining goblins with ease due to the powerful equipment. They earn money and upgrade their adventurer rank. They then travel to the city of Brunne, where they encounter merchants and adventurers, including Green, a familiar face from their earlier encounter. Heihachi uses his "Status App" to scan Green, revealing his stats are significantly lower than Heihachi's and Noru Fanya's, confirming the extraordinary power of GC units in this world.
They take on various quests, including a dangerous hunt for a Cyclops, where Noru Fanya's overwhelming power is showcased. During the fight, Noru Fanya's helm is knocked off, revealing her face for the first time. She becomes extremely embarrassed and distressed, but Heihachi reassures her. They learn that healers and mages are rare as adventurers, typically joining royal academies or becoming exclusive healers in the capital. Heihachi continues to focus on accumulating magic stones for more gacha pulls, aiming to obtain powerful units like Luna Valad. He also discovers new items from the gacha, such as a "Map App" and a "Magic Bag" with infinite storage. The narrative progresses with Heihachi and Noru Fanya navigating this new world, facing monsters, and striving to understand its rules and their place within it, all while Heihachi remains driven by his desire for more gacha pulls.