A contemporary Tokyo introduction frames the central conflict through the historical tale of Taira no Masakado's rebellion against the Emperor and his execution. This account establishes Masakado's lingering spirit as a dangerous *onryō* persisting as a curse over the city, tracing his transformation across centuries from vengeful spirit into a deified guardian *kami* of Tokyo. Disturbing this spirit risks unleashing Masakado's suppressed rage against the Japanese Empire, potentially causing national havoc.

The setting shifts to 1908, introducing opposing figures: benevolent *onmyōji* Yasumasa Hirai, seeking Tokyo's prosperity, and malevolent *onmyōji* Yasunori Kato, dedicated to the city's destruction. Kato's motivation roots in appeasing his ancestors—indigenous tribes who historically resisted the Imperial court—and his plan involves wielding Masakado's awakened spirit as a weapon. He kidnaps Yukari Tatsumiya, a young woman with psychic powers, to serve as the medium for Masakado's spirit.

Key events unfold across multiple time periods: Emperor Meiji's death and Hirai's ritual suicide divine the prophecy of Tokyo's destruction in the year of the Pig. Transitioning to 1923, the Great Kantō earthquake results from Kato's manipulation of spiritual energies, awakening the "Underground Dragon." The narration further bridges the plot to 1927, outlining Tokyo's reconstruction, subway system development, and Kato's continued attempts to rouse the dragon through Yukari's daughter, Yukiko.

Maintaining an omniscient perspective, the narration links historical events like the earthquake and urban modernization to the supernatural conflict between Kato and his opposition. It concludes by underscoring the cyclical nature of Tokyo's spiritual turmoil and reflecting on the city's uncertain future following Kato's defeat.