In Japan, a powerful exoskeleton weapon known as the Infinite Stratos (IS) was created. Due to its immense combat capabilities, the IS can only be operated by women, as mandated by an international accord prohibiting its usage as a military resource. However, Ichika Orimura, a 15-year-old male, possesses the rare ability to pilot an IS. Consequently, he is enrolled in the all-female Infinite Stratos Academy, wherein students are trained to become IS pilots. At the academy, Ichika reconnects with his childhood friends, Houki Shinonono and Lingyin Huang, and establishes a bond with Cecilia Alcott, one of the IS representatives from the United Kingdom. Chifuyu Orimura, an IS master, Ichika's elder sister, and their strict homeroom teacher, leads the group. Together, they must apply their expertise and talents to safeguard themselves and the academy from the dangers that emerge throughout their gripping school life.