Franck Magne, a fresh-faced detective in Paris, is assigned his first major case involving the brutal murder of a young woman. As he dives into the investigation, he uncovers a series of unsettling similarities with other unsolved murders over the past decade. Despite initial lack of support from his superiors, Franck becomes increasingly convinced that he is dealing with a serial killer. His tenacity leads him deeper into the underbelly of the city, revealing a pattern of victims who are all young women, killed in the same brutal manner. As the pressure mounts, Franck's personal and professional lives begin to blur, leading him to re-evaluate his pursuit and the impact it's having on those around him.

Parallelly, journalist Nathalie is also drawn to the case. Driven by her own desire for truth and justice, she conducts her own investigation, which often intersects with Franck's findings. As both pursue different leads, tensions rise within the police force and the media spotlight intensifies, making the case increasingly complex. Secrets within the police department come to light, and Franck finds himself in a race against time to prevent further deaths. The lines between hunter and hunted blur as each new discovery brings them closer to uncovering the identity of the elusive killer, whose motivations are as twisted as his methods.