In the capital of Xiao lives a seventeen-year-old exorcist named Gekki Tou, the daughter of a distinguished family of spirit-banishing sorcerers who protect the imperial dynasty. Despite her elite lineage, Gekki takes on clients from the common streets rather than the court, traveling alongside her childhood friend and fiancé, Reiyou Hou, a serious young man who serves as her overseer and bodyguard. Gekki is a prodigy with extraordinary talent, but she carries a secret past of childhood abuse and a complex, strained relationship with Reiyou, who struggles with his own inadequacy in lacking sorcerous ability.

The story begins when a member of the wealthy Kohou family hires Gekki to exorcise the ghost of a recently deceased cousin that has been haunting him. She and Reiyou travel to Yangliu Island, a pleasure district, to investigate. Almost immediately after they begin, the client dies under suspicious circumstances. As more members of the Kohou family perish in a series of supernatural accidents, it becomes clear that the case is far from ordinary. The ghost of the drowned cousin appears at the gates of different Kohou branch houses, and Gekki finds she cannot banish it. The family patriarch insists the deaths are punishment from the water deity Seii娘娘, who is enshrined in a lake shrine, and refuses outside help.

Gekki and Reiyou uncover a deep family secret: the Kohou clan is hiding a history of betrayal and sacrifice tied to a precious heirloom, a mother-of-pearl garment. The lake deity's supposed wrath is actually the accumulated grudge of a woman wronged by the family generations ago, a grudge that has manifested as a vengeful spirit wearing that same garment. Gekki faces the mass of obsession at the lakeside, cuts it apart with her blade, and ends the curse. The experience forces both her and Reiyou to confront their feelings for each other and their respective places in the world of sorcery.

Later volumes expand the scope. In the third volume, Gekki receives an imperial order to investigate strange occurrences at a rural shrine on Mount Hakusai, where people have been disappearing. There she encounters the ghost of a thug who claims to have been devoured inside a cave, leading her into the dark secrets of a village bound to a flower. The series shares a fictional universe with the author's other works, such as The Raven of the Inner Palace, and interweaves occult Chinese fantasy with a slow-burn romance between a brilliant but unconventional exorcist and her rigid, earnest fiancé. The series is currently ongoing.