Witch Hunter Robin
The secret organization called STNJ catalogs and watches all people with the potential to become a 'witch'. When a witch shows signs of using their craft, the organization captures the witch and locks him or her away, never to be heard from again. Some of the organization's employees are themselves craft-users or potentials who use their abilities to capture those witches who cannot control the powers they possess.
Robin is new to the group and is a craft-user herself. In the process of capturing other witches, Robin gains much better control and understanding of her own craft, and it soon becomes apparent that someone doesn't like this fact. As Robin continues to gain understanding, will she be able to continue capturing those like her, or will she wind up next on the capture list?