While most young girls make an effort to show off their feminine charms, Futaba Yoshioka deliberately behaves like she wants to repel anyone who might be attracted to her. Ostracized by her female classmates in middle school for being a little too popular with the boys, she desperately strives to avoid a similar situation in high school by being unnecessarily noisy and graceless. Nevertheless, scattered among Futaba's unpleasant memories are the treasured moments with the boy she had a crush on, Kou Tanaka. Unfortunately, that spell abruptly ended on a sour note when he suddenly stopped attending school and never came back. When Futaba finds out that Kou has returned—with a different last name this time—she can already feel the butterflies in her stomach. However, Kou Mabuchi is not the warm boy that she remembers from her days in middle school; he is now taller, more charismatic and withdrawn—making him far less approachable. Futaba believes that if she returns to her former self, Kou will begin to take notice of her again. But is she prepared to sacrifice her bubble of normalcy and risk losing her friends in the process?

There exist few humans in this world with the ability to manipulate their souls to form powerful weapons. Dubbed "Blazers," these people study and train at the prestigious Hagun Academy to become Mage-Knights; among the students is so-called failure Ikki Kurogane, the sole F-rated Blazer. However, when the worst student in the academy sees Stella Vermillion, an A-ranked Blazer who also happens to be a princess, naked, she challenges him to a duel with dire stakes—the loser becomes the slave of the winner. There's no possible way that Stella can lose, right? As he tries to prove his strength to a world that believes him to be the weakest, Ikki gains new friends, wisdom, and experience.

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.

In Martian colony Fourth Tokyo lies a classroom of Kirishina Corporation's brightest minds spearheading aerospace development: A-TEC, led by genius engineer Kaito Sera, eagerly anticipating the arrival of their newest member. It soon becomes clear, however, that the transfer student is hardly ordinary—Nagisa Kiryuu, newly appointed chief of A-TEC and the younger brother of the corporation's CEO, is sent to shut the program down. To keep the classroom alive, Kaito and his students desperately work to develop a successor to their most powerful rocket, the X-2; meanwhile, Nagisa climbs the corporate ladder in pursuit of his own mission. In spite of this, their separate battles soon reveal that much more is going on in Kirishina Corporation than meets the eye. Classroom☆Crisis follows Kaito and Nagisa, as well as Kaito's younger sister Mizuki and A-TEC's test pilot Iris Shirasaki, in a story of intrigue, political warfare, and, against all odds, romance. As Nagisa and A-TEC are dragged further and further into Kirishina Corporation's conspiracies, friendships grow and pasts are unveiled as they fight to avert their classroom crisis.