On the banks of the Ardèche, near Vallon-Pont-d'Arc, kayakers find the body of the museum president of a recently discovered Paleolithic cave. A 40,000-year-old carved stone was embedded in his neck. To investigate, Captain Manon Ferret-Duval of the research section teams up with her counterpart Riad Lekcir. They must overcome a shared past: she is convinced that her partner's older brother is responsible for the murder of her parents in 1994. Riad has no doubt that Kamel, now deceased, is innocent.

Sophie gets the wrong target when she shoots the bookseller. A bookseller loved by the whole neighborhood? She accuses him of using their love nights as a weapon to destroy her by exposing her on the Internet as pornographic material. Her trial will bring to light the ordeal of an ordinary young woman victim of cybercrime, and the devastation on her children, her loved ones, even her job... But in the absence of evidence, will we believe her?

The story revolves around the people of Sète, France. Their lives are punctuated by family rivalries, romance and scenes from daily life, but also by plots involving police investigations, secrets and betrayals.

Lucie, a young French woman passionate about perfume, sets out on a research trip abroad. Her tragic destiny crosses paths with Younes, a penniless taxi driver who delivers her into the hands of Islamist kidnappers, and with Abou, a jihadist also from France.

Murders in... is a collection of French-Belgian police TV movies taking place each time in a different French city and region.