Ichirou Suzuki, a programmer nearing his thirties, is drowning in work. Worn out, he eventually has a chance to catch up on sleep, only to wake up and discover himself in a fantasy RPG world, which is mashed together from the games he was debugging in reality. In this new place, he realizes that not only has his appearance changed to a younger version of himself, but his name has also changed to Satou, a nickname he used while running beta tests on games. However, before Satou can fully grasp his situation, an army of lizardmen launch an assault on him. Forced to cast a powerful spell in retaliation, Satou wipes them out completely and his level is boosted to 310, effectively maximizing his stats. Now, as a high-leveled adventurer armed with a plethora of skills and no way to return to reality, Satou sets out to explore this magical new world.

Hacka Dolls are AI that scan a person in order to tailor news recommendations and information to their users. These widespread, personalized robots have served many citizens, from government officials to professional sports players. A severe drop in quality leads to the production of three substandard Hacka Dolls. Due to their personality defects, they are sent to Earth, tasked with advancing humanity in whatever way they can. Whether it be encouraging a fujoshi to sell a doujinshi at Comiket or performing in an idol group, the three dolls will complete any task as long as it abides by their moral compass. Despite their shortcomings, they take their mission very seriously and always try their best to assist everyone with incredible enthusiasm.

At the tender age of 14, high school student Naru Sekiya finds that she pales in comparison to the fairy tale princesses she adores so much, not to mention the ideal girl she wants to be in contrast to her peers. Her childhood friend Yaya Sasame is enjoying herself with her school rock band, while her other childhood friend Tami Nishimikado is a member of the student council. Desiring the strength to take the next step forward, Naru has wanted a magic key to open her timid heart since the start of high school. During one moonlit night, Naru encounters what she believes is a cute fairy standing atop a torii gate who shortly invites her to dance with her. The next day, she discovers that the "fairy" was not only just an ordinary girl, but also a transfer high school student from America! Excited to meet Naru again, Hana N. Fountainstand encourages her to help her start a club for yosakoi, a festive type of Japanese dance that Hana has been entranced by since childhood. Though initially terrified of Hana's enthusiasm and the thought of being seen dancing, Naru slowly finds herself immersed in the art of yosakoi and assisting her new friend achieve her dream—for the path for a maiden such as herself is at the mercy of the wind!

When it comes to the fantasy MMORPG Cross Reverie, none can match the power of the Demon King Diablo. Possessing the game's rarest artifacts and an unrivaled player level, he overpowers all foolish enough to confront him. But despite his fearsome reputation, Diablo's true identity is Takuma Sakamoto, a shut-in gamer devoid of any social skills. Defeating hopeless challengers day by day, Takuma cares about nothing else but his virtual life—that is, until a summoning spell suddenly transports him to another world where he has Diablo's appearance! In this new world resembling his favorite game, Takuma is greeted by the two girls who summoned him: Rem Galeu, a petite Pantherian adventurer, and Shera L. Greenwood, a busty Elf summoner. They perform an Enslavement Ritual in an attempt to subjugate him, but the spell backfires and causes them to become his slaves instead. With the situation now becoming more awkward than ever, Takuma decides to accompany the girls in finding a way to unbind their contract while learning to adapt to his new existence as the menacing Demon King.