The king of Natra has fallen ill, leaving the only hope for his kingdom to his son, Prince Wein Salema Arbalest. Known to be capable and wise, he is the perfect candidate to become the prince regent. However, if the prince has anything to say about the matter, he would rather sell off the Kingdom of Natra to the highest bidder! Since he wields the authority of the throne, no one can stop Wein from auctioning off the country and using the profits to retire in comfort. All he needs to do is raise the value of the small kingdom to maximize his gains. But whether Wein's grand plan will succeed remains to be seen, as his wit often surpasses even his own expectations—much to the benefit of the oblivious citizens of Natra.

A nameless sword wakes up to discover he has been reincarnated from his former life as a human. With his power of telekinesis, he moves around this new world, acquiring several skills and abilities. When the sword comes upon a forest filled with monsters, he meets a young girl fleeing from a beast. Grabbing the sword, the girl easily defeats the monster. After introducing herself as Fran, she names the sword Shishou and officially becomes his wielder. The two set out to become adventurers, but unfortunately for Fran, she is a member of the Black Cat Tribe—a Beastkin group with a bad reputation. No member of this tribe has ever evolved into a mightier beast, but Fran plans to be the first and achieve her parents' dream. As Shishou promises to remain her sword until she attains her goal, they form an unstoppable partnership of impressive strength.

The dispassionate, transforming assassin Golden Darkness returns to peer deeper into the mysteries surrounding her new life, while a sinister Nemesis manipulates her younger sister Mea from the shadows. Along with their newly discovered mother, Tearju, this previously estranged family quickly becomes the center of everyone's attention. On the other hand, Princess Momo's Harem Plan stands on shaky ground amidst Rito's inability to confess to his longtime crush Haruna, who has grown feelings of her own. But things aren't as peaceful as they seem; an evil force looms amidst the innocuous commotion, threatening to eclipse the love, happiness, and friendship of Rito and his harem. Only the light of love can hope to banish the shadow.

Academy City stands at the forefront of scientific and technological progress, best known for their development of espers: those capable of wielding superhuman abilities that alter the rules of reality. The most powerful among them are the Level 5s, and the one known as Accelerator reigns supreme, even after being weakened by a severe brain injury. By his side is the young girl known as Last Order, whom despite his cold demeanor, he holds closely and vows to protect at all costs. Though Accelerator may be recovering from his injury, the dark side of Academy City never rests, and so he finds himself unwillingly caught up in the midst of a new conflict. When a mysterious young woman approaches Accelerator in pursuit of Last Order, the highest-ranked esper is confronted by a venomous organization that has taken root in Anti-Skill, Academy City's peacekeeping organization. With dangerous forces on the move that threaten to put Last Order and her sisters at risk, the self-proclaimed villain prepares to step into the darkness once again.