Originally, Aichi Coexistence Private Academy was an all-girls school for privileged young ladies until it was decided that it would become co-ed. The fearful girls were permitted to bring weapons to protect themselves, and then a vigilante group was established called the “Supreme Five Swords." When rebellious Nomura Fudou is sent to the academy, he is given two options: act and dress like a girl or be expelled!

(Source: Sentai Filmworks)

 AnimeRulz is the best site to watch Armed Girl's Machiavellism SUB and DUB in HD quality.