In the shadowy streets of Lügenberg—a city where humans and demihumans coexist in uneasy peace—an unusual detective agency operates far beyond the reach of common law. There, vampire investigator Arne Neuntöte pursues the uncanny, blurring the lines between violence and truth. Everything begins to shift when Lynn Reinweiß, a noblewoman whose fascination with vampires outweighs her grasp of their danger, crosses paths with Arne. The two form an alliance in pursuit of bloody mysteries that emerge from Lügenberg's darkest corners as death and deception surface beneath the city's gothic veneer. Through each case they solve, Arne and Lynn discover time and again that truth is more elusive than what any surface can reveal. [Written by MAL Rewrite]

Arne no Jikenbo is based off the RPG Maker game of the same name.