After he is dismissed from his umpteenth job, Momo is kicked out of the family home by his fed-up father. He immediately joins his buddy Manu, who is also penniless having just lost his job at a cafeteria. The two decide to ask shady nightclub owner Sammy for a job, and he promptly hires them to transport back two statuettes from Amsterdam. Momo and Manu soon find out that these art objects are stuffed with drugs, but still manage to carry out their mission. They receive one kilo of grass in exchange, which they sell immediately. But while the business is lucrative, they discover that it's not so easy to become a full-fledged drug dealer...
The "black robe" in the title of this suspense film belongs to a female lawyer, Florence Nat who has just lost a case in which she defended Simon Risler, a man wrongly accused of murder. Risler escapes before he can be put in prison, and seeks help from attorney Nat in finding the real killer, partly by going after the police inspector who framed him in the first place. A retired surgeon, in the process of setting up a drug rehab clinic gets involved in solving Risler's case, and soon the solution seems to be pointing to high-ranking figures with every desire and ample means to keep the truth well-hidden.
