Kazuya Kinoshita is a 20-year-old college student who has a wonderful girlfriend: the bright and sunny Mami Nanami. But suddenly, he doesn't. Without warning, Mami breaks up with him, leaving him utterly heartbroken and lonely. Seeking to soothe the pain, he hires a rental girlfriend through an online app. His partner is Chizuru Mizuhara, who through her unparalleled beauty and cute demeanor, manages to gain Kazuya's affection. But after reading similar experiences other customers had had with Chizuru, Kazuya believes her warm smile and caring personality were all just an act to toy with his heart, and he rates her poorly. Aggravated, Chizuru lambastes him for his shameless hypocrisy, revealing her true pert and hot-tempered self. This one-sided exchange is cut short, however, when Kazuya finds out that his grandmother has collapsed. They dash toward the hospital and find Kazuya's grandmother already in good condition. Baffled by Chizuru's presence, she asks who this girl might be. On impulse, Kazuya promptly declares that they are lovers, forcing Chizuru to play the part. But with Kazuya still hung up on his previous relationship with Mami, how long can this difficult client and reluctant rental girlfriend keep up their act?

In an Edo-era Japan lush with a variety of sword-fighting styles, Shichika Yasuri practices the most unique one: Kyotouryuu, a technique in which the user's own body is wielded as a blade. The enigmatic seventh head of the Kyotouryuu school, Shichika lives quietly in exile with his sister Nanami until one day—the wildly ambitious strategist Togame barges into their lives. Togame brazenly requests that Shichika help in her mission to collect twelve unique swords, known as the Deviant Blades, for the shogunate. Shichika accepts, interested in the girl herself rather than petty politics, and thus sets out on a journey. Standing in their way are the fierce wielders of these legendary weapons as well as other power-hungry entities who seek to thwart Togame's objective. In order to prevail against their enemies, the duo must become an unbreakable team as they forge ahead on a path of uncertainty and peril.

With the initiation of the Patrian civil war came the creation of half-beast, half-human soldiers—a development of the outnumbered Northerners in a desperate attempt to counter the overwhelming Southern forces. Able to quickly dominate battlefields and achieve victory with ease, the soldiers' godlike abilities earned them the name Incarnates. However, as the war raged on, the Incarnates encountered a problem involving the beasts inside them that they were unable to rectify by ordinary means. Once the war was over, mysteries and accounts of the Incarnates submitting to the misfortune of their war days surfaced. Aware of the horrors they faced during the war, Special Sergeant Major and former captain of the Incarnates Hank Henriette becomes a Beast Hunter—those who take the lives of Incarnates who have succumbed to the issues they experienced on the battlefields. After witnessing her father, a former Incarnate soldier, meet his end at the hands of one such Beast Hunter, Nancy Schaal Bancroft resolves to hunt the man who took her father's life. However, Nancy's eye-opening encounter with the Beast Hunter influences her to instead seek the reason behind her father's death and the Incarnates' problematic existence in society.

Yuu Izumi leads a high school life filled with one mishap after another. No matter how improbable the situation, unfortunate events strike him at every turn. In possession of such terrible luck, Izumi enters his second year with a single wish in mind—to spend more time with his affectionate girlfriend, Micchon Shikimori. Cute, athletic, and caring, Shikimori is immensely popular at their school. But since they began dating a year ago, Izumi has witnessed a surprising side to his otherwise adorable girlfriend: when the need arises, she turns incredibly cool! His misfortunes are easily avoided when she is there to protect him with an awe-inspiring look on her face. Charming in every way, she never ceases to make his heart skip a beat. Unfortunate as he may be, Izumi is sure to see his days of bad luck end thanks to the cute yet cool Shikimori.