Blessed with eyes that are able to perceive the otherwise invisible youkai, Takashi Natsume hides his ability from his newfound family and friends to protect everyone's peaceful daily life. Nonetheless, Natsume never fails to show the same kindness to the benevolent youkai and happily returns their names by using the infamous Book of Friends he inherited from his late grandmother, Reiko.
Meanwhile, the exorcist clan Matoba still wishes for Natsume to join their ranks due to his overwhelming gift. However, Natsume firmly rejects the clan's invitation since not all exorcists are as reasonable as his friend Shuuichi Natori, and many improperly and indiscriminately seal away every youkai in their way. Unsatisfied with Natsume's answer, Seiji Matoba blackmails Natsume into attending a grand gathering of powerful exorcist families. Natsume soon finds himself in the company of dangerous people and youkai alike. But even then, he continues to defy the exorcists' hard-handed methods and believes that peace between both worlds is possible.