Kurayukaba

The Ootsuji Detective Agency is struggling for business. Sotaro, a detective, and his young partner Saki accept a risky job during the city's festival season, when a series of unexplained disappearances take place. A journalist hires Sotaro to look into the cases, pointing to the Dark—a chaotic underground area of the city. Sotaro assigns the task to Saki, but becomes worried when Saki also vanishes. Forced to take action, Sotaro enters the Dark to find him. There, he encounters dangerous groups such as the Laughing Masks and a rogue police unit operating the armored train known as Demon 463.