Shinogi Inumata is an eighteen-year-old orphan with no job, no dreams, and no will to live. His one unusual trait is the ability to see and cut ghosts, a power he finds more troublesome than useful. While walking home from another failed job interview, he encounters a beautiful female spirit. Perceiving her as a threat, he uses his power to kill her on the spot. He is shocked to find the very same woman waiting for him in his apartment, fully regenerated. She introduces herself as Yaergnacht Finsternis, a former member of the Apostles, and presents him with an ultimatum: become her husband or die.

Yaergnacht explains that the Apostles are servants of God who hunt and kill any human they believe has strayed from divine creation. To fight these powerful enemies, she needs Shinogi. Despite the absurdity of the situation, Shinogi accepts her proposal. The story follows this unlikely newlywed couple as they battle the Apostles, with Yaergnacht possessing the power to create anything she desires, including the apartment building they live in, and Shinogi using his unique ability to cut down spiritual beings.

The setting is a contemporary Japan where supernatural forces hide in the shadows. The series follows their battles against the Highlander, the human agents of God who serve as the primary antagonists. As the recently formed husband-and-wife team face these enemies, Shinogi slowly finds purpose in a world that once seemed meaningless. Major narrative arcs include the initial encounter and forced cohabitation, the revelation of Yaergnacht's past as an Apostle, and their first major battles against the forces that seek to eliminate those who deviate from God's plan.