In a dark and foggy early 20th-century Paris, a series of brutal murders shakes the quiet life of its inhabitants. It all begins when two women are found murdered in a horrifying crime that leaves the police completely baffled. The crime scene is not only macabre, but it also presents clues that defy all logic, causing the detectives to desperately search for the culprit. As the investigation progresses, the atmosphere grows increasingly tense, and the clues seem to lead to dead ends.
However, hope arrives in the form of an eccentric and brilliant detective. With his analytical mind and his ability to notice details that others overlook, he embarks on the task of solving the mystery that has the city on edge. As the plot unfolds, the investigator delves into a hidden world of fairs, circuses, and peculiar characters, where nothing is as it seems.
In a race against time, a dark secret is unveiled that connects the victims to a strange creature that may hold the key to the enigma. Intrigue intertwines with fear and madness, leading the detective to an unexpected confrontation with the real culprit, revealing that some truths are more terrifying than fiction. The film becomes an exciting journey through the human mind and the darkest aspects of nature, where reason confronts the inexplicable.