There was no heart in your mother's corpse.

Kikumitsu Gemma is a high school girl who has recently lost her mother and now lives with relatives while working part-time at a local cafe. She is cheerful but has a somewhat detached demeanor, which may stem from her unusual nature as a second-generation demon, the child of a human mother and a demon father. As a Nisei, a term for someone born outside their ethnic homeland, Kikumitsu is ethnically demonic but was born in the human world.

Her demonic heritage grants her incredible resilience and strength, allowing her to easily survive a knife to the face or remove a person's head without hesitation. Despite these abilities, her life is relatively ordinary as she works to save money, with her primary goal being to finally visit her absent father. The central mystery of the story revolves around the nature of this father and what exactly he is.

The narrative follows Kikumitsu as she navigates the line between the human and demon worlds, exploring the life of someone who belongs fully to neither. The story begins with her mundane routine of school and a part-time job, but the implications of her parentage and her quest to find her father drive the plot into supernatural territory. The opening premise is established with the shocking statement about her mother's corpse, immediately setting a tone where horror and the everyday collide in a story that is for the most part a fun and relaxing read.