Despite being burdened with crippling debt to the morose Haruitsuki Abeno, Hanae Ashiya has come to enjoy his job as an exorcist. His ability to communicate with youkai has given him a sense of responsibility regarding the magical creatures, and he continues to work hard to send them to their true home in the Underworld. As Ashiya’s life finally stabilizes, the youkai threaten to upset it once again. Knowledge of his existence has begun to spread, and not everyone is happy to have a human working for the Mononokean, the interdimensional tea room. But one day, a simple visit to the Underworld draws the attention of those in power, and Ashiya soon learns that not every youkai is willing to go along with Abeno's plans.

The boisterous student Kaname Chidori and soldier Sousuke Sagara are enjoying a blissful high school life. However, their peaceful days are disrupted by the threatening terrorist organization Amalgam. Leonard Testarossa, a member of the organization who possesses Whispered, seeks to procure Kaname and her knowledge. Kaname and Sousuke's battle against Amalgam starts right in their own neighborhood, which eventually takes them on a hunt around the world. From the exotic lands of Laos to the barren Mexican coast, Sousuke must gather intelligence to bring down Amalgam. Meanwhile, Kaname's abilities grow, but so does her frustration as her resolve withers. Caught up in an intense game of hide and seek, as well as strategic plots, the pair try to connect and push beyond their own limits.

Despite having a good reputation as one of the most seasoned guards in the local guild of Mebuki, Kikuru Madan believes he has been wasting his youth and hopes to spend the rest of it like any other person. However, his conscience prevents him from retiring at present, as he worries about the guild's future without him. Coincidentally—as if to help him find his successor—the guild's receptionist, Enome, assigns Kikuru four fresh recruits: the energetic beastwoman Hitamu Hitamuki Kyan, the prodigy Maidena Ange, the laid-back Toxico Dannar, and the stalwart Hanabata Nohkins. Although each of them possesses significant talents, they also display characteristics that detract from their potential—including Hitamu's extreme clumsiness and Hanabata's unintentional perverseness. As if there was not enough to deal with, the monsters outside Mebuki's walls start exhibiting odd behavior by targeting women salaciously, causing the party endless problems in more ways than one. Nevertheless, Kikuru is committed to retiring early; to achieve his goal, the guidance he gives the trainees will be absolutely essential.

Third-year high school student Jirou Yakuin is in love with his childhood friend and classmate, Shiori Sakurazaka. Thus, he hopes to be paired with her for the marriage practical: their school's practice of randomly selecting boy-girl pairs to live as pretend married couples while monitoring and rating them on how close they have gotten. Meanwhile, the lively Akari Watanabe wants to be assigned to her crush, the popular and good-looking Minami Tenjin. Much to their dismay, Jirou and Akari find out that not only have they been paired together, but so have Shiori and Minami! Determined to be with their crushes, Jirou and Akari strive to earn as many points as possible, as the top 10 pairs earn the right to switch their partners—so long as both couples agree.