Picardie, 1963. In the dead of night a truck drops a group of illegal workers by a deserted stretch of canal - days later, one of them is found stabbed to death and Inspector Lucas Rocco has a new case to solve. Trawling the Algerian community for information is a sensitive issue, one that terrifies his bosses who force Rocco to tread carefully. Too carefully for Rocco's liking. To add to his problems, amongst the illegal immigrants is a young woman on the run from her brutal gangster husband, Samir Farek - a man with a big agenda: to take over as gang lord in Paris, and willing to dispose of anyone who gets in his way...