Brave: Gunjyo Senki description:

Like most students Aoi is a member of an extracurricular club at school and practices archery. Due to ample practice, Aoi is good at it. The members are mostly good friends. All is well until blitz and thunder hit the premises and the school and its students are not the same anymore. They are transported to a different era, one in which samurai roamed Japan. The students are not only caught in an anachronism, but they are also in the midst of a historic battle.