After a decade spent fighting monsters in the Shadow Labyrinth—a growing dark cloud of magic that threatens to engulf the world and destroy all life—mage Desir Herrman and his five companions finally face their last foe: the dragon of destruction Boromir Napolitan. Although the group of heroes manages to slay this formidable opponent, the tremendous amount of mana stored within the dragon's body is released in an unstoppable explosion that annihilates the rest of the world. However, instead of dying, Desir is sent back 10 years into the past with complete memories of events to come. He enrolls at Hebrion Academy, determined to put an end to the classist prejudice plaguing the magical world that will ultimately lead to the demise of humanity. Unfortunately, his struggle begins early on during the entrance exams; although he is ranked first of his group, Desir is assigned to the Beta Class, the default class for commoners. Now, Desir's next objective is to rally someone to his cause that he could not save in his previous life: the wind mage Romantica Eru. Then, Desir will have to show his worth to the Alpha Class with his newly formed party if he wants to ultimately save as many lives as possible.

Konoha Akisato's love for bishoujo games—a type of entertainment focused on interactions with beautiful girls—has always nurtured her aspiration of becoming a popular artist. However, as Konoha secures her first job as a sub-illustrator at the game company Blue Bell, she confronts the harsh reality surrounding her favorite genre. In 2023, the bishoujo game industry is overrun with cheap, repetitive, and low-effort releases, with Blue Bell at the core of the problem. After stumbling upon a vintage game store and reminiscing about the impressive titles of the past, Konoha suddenly winds up in the year 1992—just as the bishoujo game industry was beginning to flourish. Konoha struggles to accept her new circumstances until she joins Alcohol Soft, a small game company willing to employ her as an illustrator. Although she believes her skills from the future will propel her to success, technology and illustration are considerably old-school, and she must promptly adapt if she wishes to fulfill her dreams.

Orphan Himari Momochi's only link to her late parents is the house they secretly bequeathed her, which she does not learn of until her 16th birthday. Thrilled by the opportunity to know more about her family, Himari arrives at the rumored haunted house and is bewildered to find three young men already living there: Aoi Nanamori, who identifies himself as the guardian of the place, and his two familiars, Yukari and Ise. Although they allow her to stay overnight, they warn her to leave the next day so she can avoid harm from ayakashi—wandering spirits that sometimes attack human beings. Surprisingly, Himari is unaffected by her spectral encounters and determined to move in to the residence. After she discovers that Aoi had become guardian unwittingly and is now confined to the property, forgotten by the outside world, her resolve only grows stronger. Touched by his story, Himari decides to find a way to free Aoi from his dim fate, and she convinces the three Momochi House protectors to accept her as their landlady. However, the mysterious Kasha who keeps sending hostile ayakashi to Himari's new home seems to have darker plans for Aoi's future.

As the graduation ceremony at Katagiri High School comes to an end, Kyouko Hori, her boyfriend Izumi Miyamura, and their friends begin to look back on their time as students. The moments they shared together may be fleeting, but each one is a colorful piece of their precious memories.