The intrepid Léo, self-proclaimed "best cop on the Riviera", learns that her colleague and brother Ludo has been killed in Hamburg. While she wants to discover the truth, she is forced by her superior to let a German supercop do it. There is no question of letting a "shame in a suit" investigate, especially when she discovers that it is, in fact, attractive and highly-trained Mélanie. Forced to team up, these two women with characters as explosive as they are opposite have no idea that Nice is facing an imminent threat and that they share an unimagined link.