Jimmy is a low-ranking member of a gang in Silent Bay City, one of the world's few underground cities with a 1920s aesthetic ruled by organized crime. Having lost his family and fallen into debt, he has no path forward but to follow orders from violent superiors. His life changes one night when he meets a nameless girl on a rooftop, a meeting that prevents him from taking his own life. He bonds with the girl, naming her Lili, and learns she speaks of vampires lurking at gang headquarters. After a horrific incident where Jimmy witnesses his fellow gang members slaughtered by a shadowy figure in a body disposal shed, he is betrayed by corrupt police and brought before his gang leader. The leader reveals himself to be a vampire and prepares to kill Jimmy before a massive wolf-like creature descends, brutally tearing the vampire apart. The girl Lili is revealed to be this werewolf, and she is accompanied by a mysterious man named K, who tells Jimmy they are the Night Hounds, an organization that hunts vampires.

Following this encounter, Jimmy is recruited by the Night Hounds, an anti-vampire special investigations team. He agrees to work with them but is given a dangerous assignment: infiltrate the very gang that once controlled him, the Lakeside Fellows, which is secretly infested with vampires. Gaining the trust of an underboss named Dorothera, Jimmy is sent on a mission to a rumored haunted mansion known as the Evermist Funeral Home, a storage site for a rival gang faction led by Leo. Inside, he must survive both the supernatural horrors of the location and the constant threat of being exposed as an infiltrator. The narrative escalates as Jimmy finds himself caught in the middle of a three-way struggle between the human criminal underworld the Lakeside Fellows, the hidden vampires manipulating them, and the Night Hounds hunting the creatures of the night. Later arcs see Jimmy attempting to earn the trust of a gangster named Hawk, leading him to a theater where twin sisters perform a demonic magic show, while Lili faces psychological threats from a shadowy figure named Marna emerging from her own past.