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 semi-independently under the Protection and Research Agency, they use special rings to transform and gain weapons to use in their battles. One particular magical huntress, the sword-swinging orphan 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 while on lunch break from school. 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?