Kageyama Tobio is a Witchhunter and part of the Gold Unit - the second-most renowned group belonging to the Royal Extermination Corp, or the REC. Employed by the king of Karasuno Kingdom to hunt down dangerous magic-users that threaten the safety of their kingdom and the natural world, he has everything he could ever want or need. His only goal is to one day join the Black Unit; the personal guards of the king himself and the most respected members of society. But to achieve that goal, he must first kill the most powerful of the six classes of Witch: a Thaumaturge. But those are few and far between. In fact, the last known Thaumaturge was killed by the king himself nearly a decade ago. Finding one is hard enough - not to mention the fact that his superior seems to have a grudge against him and his fellow soldiers don't take him seriously. With all these obstacles, Kageyama's dream seems to be slipping farther and farther away... Until one fateful day, that is. A call to aid a village plagued by a Witch's curse reveals a Thaumaturge that has been hiding under the kingdom's nose for nearly 17 years: a redheaded boy with a spitfire personality and no love for the king. Kageyama and his Unit are tasked with bringing the dangerous Witch back to the king for sentencing, but throughout the long journey home, Kageyama finds his hard outer shell slowly beginning to crumble as he grows inexplicably closer to a boy that is supposed to be 'deadly' - a boy that could easily kill him. As his feelings - and doubts - begin to grow, Kageyama must ask himself what is right: Following orders, or following his heart.