When magical beasts cross into Japan through portals, magical huntresses (and some magical huntsmen) are there to slay them. Consisting of teenagers and young adults working with the Protection and Research Agency, they use special rings to transform and gain weapons. One particular magical huntress, the sword-swinging Ruka Kishio, is asked to join a small group of these hunters led by the charismatic Hana Miyashita after Ruka easily kills a beast by herself. She soon finds herself bonding with the other members of the Fox Knights, in particular their second-in-command and only boy Yoshiro Arikawa despite the two of them frequently arguing, and she also finds herself rising through the ranks.
However, Hana has deeper ambitions to restore the honor of her family name, and she aspires to attain power by any means necessary. Can Ruka help Hana with her dreams, or will she be swept up in them?