It's 1863, the twilight of the shogunate, and Japan is on the cusp of monumental change. The streets of the nation's capital are soaked in blood as political upheaval and rising tensions between masterless, wandering ronin and government samurai set the stage for one of the most turbulent times in Japan's history. Young orphan Nio is no stranger to the harsh realities of the world, and yet he can't help but cling to his burning passion for justice and desire to change the world for the better. One day, he crosses paths with two men who will become central figures of the coming revolution: Hijikata Toshizo and Okita Souji, two of the founding members of a group of hated ronin known as the Miburo—who would later become known as the Shinsengumi. Inspired by the efforts of the so-called "Blues Wolves of Mibu," Nio decides to join the ranks to help carve a path to the world he wishes to see. But with new betrayals and reversals every day, will Nio be able to stay true to his conscience?

Despite completing all the tasks given to them, Ainz Ooal Gown, Tanya Degurechaff, Kazuma Satou, Subaru Natsuki, and the other members of Class 2 are surprised to find out that their role as students is far from over. With no means of returning home, the class of eccentric personalities is still mysteriously stuck in the unfamiliar world. Although, as they are becoming quite fond of each other, spending more time together does not sound that bad. With the unexpected arrival of new transfer students, the comedic antics of our beloved characters continue to grow. Thus, their bizarre yet nonchalant school life continues.

Takes place in the year 2200, where Japan has become a land of cats as the human population's birth rate has declined. In this future world, cats can talk, learn, and work. The story follows a high school girl and her argumentative cat.