An exoskeleton weapon engineered by Japan, Infinite Stratos (IS) can be piloted only by women. Its power and combat prowess are so immense that an international treaty has been signed banning its use as a military asset. When it is discovered that 15-year-old Ichika Orimura is the only male capable of steering an IS, he is forcibly enrolled in the Infinite Stratos Academy: an all-female boarding school, the students of which graduate to become IS pilots. At this training school, Ichika is reunited with two of his childhood friends, Houki Shinonono and Lingyin Huang, and befriends Cecilia Alcott, an IS representative from the United Kingdom. Guided by the legendary pilot Chifuyu Orimura—their strict homeroom teacher and Ichika's older sister—Ichika and the girls will need to use everything at their disposal to defend themselves and their academy against the dangers that will arise during the course of their thrilling school life. [Written by MAL Rewrite]

Kyouhei, after moving away to Tokyo from his old town to get away from the events that happened, is on a goukon with his friends, including his old neighbor, Shiba. After drinking for a whole night, he and Shiba discover a dead, bloody body in the elevator. He is told by his younger sister, Utao with her Kamisama Doll, that Aki, an old friend, and his Doll are the culprits responsible.

Kouta has girl troubles of the supernatural sort. For some reason, he keeps attracting the attention (and affections) of animal spirits! Having spent most of his life in the country, Kouta is understandably nervous when he moves in with his grandma to attend a high school in the big city. He hoped to make a good impression, but having Chizuru, a beautiful fox spirit, hanging off his arm didn't seem to be the sort of image he wanted to have. She's not alone in her love for Kouta, either. Nozomu, a wolf spirit, as well as other youkai have their sights set on the hapless country boy.

Shinobu Oomiya once left Japan to participate in a homestay in England. During her time there, she became close friends with Alice Cartelet, the daughter of the family she was living with. However, when it was time for Shinobu to return to Japan, the two were able to express their sorrow despite the language barrier between them. Five years later, now a first year student in high school, Shinobu receives a letter by air mail in a language she does not understand. This letter is penned by none other than Alice, detailing her own homestay in Japan. In fact, Alice will be attending Shinobu's high school and living with her! Alongside their friends Youko Inokuma, Aya Komichi, and Karen Kujou, the five girls attend school together and learn about what their different cultures have to offer, day after day. [Written by MAL Rewrite]