The day is as normal as it can be in high school as the students peacefully go about their everyday activities until an unprecedented catastrophe strikes the school, killing every person in its wake. Guided by what seems to be a miracle, a handful of students are fortunate enough to be reincarnated into another world as nobles, princes, and other kinds of people with prestigious backgrounds. One girl, however, is not so lucky. Being reborn as a spider of the weakest kind, she immediately experiences the hardships of her dire situation. Even so, she must press on to survive the numerous threats that endanger her life. Discovering that her new world has a system like that of an RPG, she tries her best to hunt prey and defeat monsters to level up and evolve. As she gradually grows stronger, she hopes one day her efforts will be rewarded, and that she will be granted a better life.

Ever since her late mother took her to an aquarium when she was young, Tsukimi Kurashita has been obsessed with jellyfish, comparing their flowing tentacles to a princess's white dress. Now living with five other unemployed otaku women, 19-year-old Tsukimi spends her days as a social outcast dreaming of becoming an illustrator. However, her life changes forever when one day, a beautiful woman unexpectedly helps her save a jellyfish in a local pet store. From then on, the stranger—confident, fashionable, and the complete opposite of Tsukimi and her roommates—begins to regularly visit the girls' building. This trendy hipster, though appearing shallow at first, harbors some secrets of her own, starting with the fact that she isn't really a girl at all, but a wealthy male college student named Kuranosuke Koibuchi!

Chihiro Enomoto is a freshman that just got to a new school called Rikkyoin High School. He lost his parents in a traffic accident when he was 10. Since then, he has been living only with his elder sister Shinobu. He is good at cooking and cleaning, and does all the housekeeping jobs. He fell in love with Tokino at first sight when he met her in the school library on the first day of school. Another girl named Ritsuko, a childhood friend of Chihiro and the chair of student council, falls in the love with the boy instantly after this long-awaited reunion. But she is not the only one who is in love with him. This is the story about a one-year campaign among the candidates for the next students government leaders, who are also chosen by the lot (kujibiki), in order to gain the position. (Source: ANN)

Special episodes included in the Blu-ray and DVD boxes of Kuma Miko.