Years ago, humanity almost got wiped out by huge magical armored insects that had become too strong and aggressive to handle. Because of these giant bugs, humans do not live on the earth anymore, but in floating cities instead. However, this does not mean that everything is lost, because the wizards from prestigious floating wizard academies are fighting these monsters. Kanata Age is a young man now labelled as a traitor even though he was once praised as the Black Master Swordsman. He gets a chance to repair his reputation by instructing the team E601, which seems to be facing some difficulties. It consists of three girls, Misora Whitale, Lecty Eisenach, and Rico Flamel, each with problems of their own. It appears that Kanata will get in deep waters more than once because of them...

Haruka Shinozaki has been interested in the class representative, Akiho Kousaka, since his first year in high school. She is attractive, good at sports, and is an all-around model student. Since they are in the same class this year, Shinozaki decides to confess his feelings—and, to his shock, Kousaka agrees to be his girlfriend! However, he finds that Kousaka is a bit stranger than he first thought: this seemingly perfect girl has never been in a relationship. But even though she is inexperienced, she vows to please Shinozaki in every way she can... such as learning multiple sex positions or his fetishes. Shinozaki tries to assure her that her studies into such subjects aren't necessary, but Kousaka devotes herself to making him happy in more ways than one.

Makoto Niwa meticulously tallies the amount of positive and negative youthful experiences he engages in as if to grade his own life. When his parents go overseas, he moves to a new town to live with his aunt, welcoming the change and ready for a fresh start. However, as ordinary as he had imagined his adolescence to be, he could never have taken the existence of an enigmatic long-lost cousin into account. Upon moving into his aunt's house, he discovers the cousin he never knew about: Erio Touwa. Despite being Makoto's age, she couldn't be more different: Erio chooses to wrap herself in a futon all day rather than to go to school. She even claims to be an alien, and with a speech pattern and personality to back it up, any chance of Makoto's dreamt-of normal life is instantly tossed out the window. As he meets a string of other eccentric girls in town, Makoto must face the possibility of seeing his youth points in the red. However, he might be surprised by how thrilling an abnormal youth can be.

As another school year begins drawing to a close, the third-year high school students move steadily toward the next milestone of their lives: graduation. Among them are Mio Natsume, a girl burdened with lingering feelings; Hazuki Morikawa, a member of the concert band but distant from the others; and Haruto Souma, an athlete obsessed with baseball. Meanwhile, second-year student Ena Komiya seeks to revive the photography club to its former glory, refusing to let the organization be disbanded. Though this group lacks a strong connection with one another, their lives suddenly cross paths with the arrival of a third-year transfer student. While a transfer so close to graduation is unusual for most, it is business as usual for Eita Izumi. Due to his father's work, he has never been able to stay in one place for very long. But as luck would have it, their most recent relocation has returned Eita to his hometown for his final semester of high school. For better or worse, it also sparks the rekindling of old relationships left behind in the past. With graduation already causing its own share of anxieties, Eita's sudden arrival brings these students' carefree days to an abrupt end. Long-forgotten memories, deeply buried emotions, and inspiring new passions—everything is brought to light in their bittersweet final semester.