Three years after his conviction for drug trafficking, Erich Kessel is about to be released from prison. It's a particularly trying time for this addiction-free former narcotics officer, whose seriously ill daughter has just died. With his wife, Claire, ready to give him a second chance after years of separation, and his former colleague and friend, Superintendent Mario Diller, having found him a job as a bartender, Kessel is determined to prove himself beyond reproach. But shortly before his release, the double murder of a young drug dealer and his fiancée, daughter of the powerful Syrian crime boss Walid Schukri, threatens to ruin his fine promises. The latter, who is serving a long sentence alongside Kessel, offers him a handsome sum to catch his daughter's killer. For the former commissioner, now broke, the temptation is great to accept this juicy contract, the ultimate investigation on the frontier of legality.