Two years after the death of her mother, young noblewoman Lynn Reinweiß lives in a home still haunted by grief, her father unable to accept the loss and often wandering into the night. One evening, she follows him and stumbles upon a brutal murder, becoming the killer's next target. Her desperate flight leads her to a mysterious coffin and the vampire inside, Arne Neuntöte. Known as the worst vampire in the city, Arne is a detective who manipulates supernatural powers and takes blood as payment for his services. Their chance encounter forges an unlikely partnership as they work together to unravel the macabre mystery surrounding her family. The story is set in the enigmatic city of Lügenberg, a European-inspired gothic metropolis where humans coexist covertly with vampires, zombies, and other supernatural beings. Arne is an ancient entity formed from the combined hearts of nine powerful vampires, but having lost eight of them, he exists in a weakened state. Lynn, a bright and cheerful fifteen-year-old with a secret obsession with vampires, provides a grounded human perspective and emotional support, complementing Arne’s occult expertise. The narrative unfolds through a series of interconnected episodic cases. The initial arc centers on the Reinweiß family murders, drawing the duo deeper into the city's occult underbelly and hidden truths about Lynn's lineage. Subsequent investigations expand to include ghost hauntings, werewolf attacks during festivals, and witch-related curses, all of which reveal fragments of Lügenberg's concealed history of supernatural-human tensions. As they solve these logic-driven mysteries, the duo confronts a broader web of curses and hidden societies, with Arne driven by the thrill of solving puzzles and a quest to reclaim his lost hearts, while Lynn uncovers secrets that tie her family’s fate to the shadows of Lügenberg.