In the year 20XX, the existence of spirits became known to humanity, and those who wielded their power came to be called “Spirit Users.” While mankind used this power to advance society, it was also not uncommon for people to use their powers for evil. Amidst this backdrop, Yui Shinonome, an overworked office worker fired from an exploitative company, obtains the power of a spirit through a strange twist of fate. With no time to grasp his new reality, Yui is dragged into the conflicts of Spirit Users and becomes a member of the Bureau of Fairy Affairs, commonly known as the BFA. Thus began his days of solving spirit-related incidents. Although Yui believed he was hired merely as a general affairs clerk, he is partnered with the BFA’s number one problem child: Mio Shinohara. Despite her immense skill, her reckless, order-defying attitude has caused all of her previous partners to quit, unable to endure working with her. While the two repeatedly clash, they gradually begin to form a deep bond. Soon, Yui learns of Mio’s tragic past—her parents were murdered by someone who misused spirit powers, leaving her with a strong desire for revenge. Furthermore, it is revealed that the spirit lending Yui its power is no ordinary spirit, but the former Spirit King who was once betrayed and lost his life. Yui makes a firm vow: to race up the ladder of success and win the heart of his beloved.