A briefcase with undisclosed contents – sought by Irish terrorists and the Russian mob – makes its way into criminals' hands. An Irish liaison assembles a squad of mercenaries, or 'ronin', and gives them the thorny task of recovering the case.
From his offices in Switzerland, Russian Igor Lipovsky is engaged in a vast and profitable gunrunning operation with Africa. The French government wants to hinder the activities of the arms dealer and sends a team to sink one of his ships heading for Angola with a load of illegal weaponry. Lisa, Brisseau, Loïc, Tony and Raymond are professionals: they carefully set up their cover, plan all their moves meticulously, and carry out orders without asking questions. Perhaps they should. The code-name of the mission is "Janus"; and just like with the ancient deity, there are two opposite faces for every aspect of the operation: the objective of the French government, the role of each team member, the presumed friend and the assumed foe...
Dr Gerald Bull was a genius at designing and building superguns (very large long range guns capable of shooting at ranges more than 100 miles). When an operational plan by the CIA to export sanctioned arms to apartheid-South Africa through him was exposed, the CIA denied all knowledge and he went to jail. He was later released, and moved to Belgium to start a subsidiary, of which a major project was to help Saddam Hussein build a new supergun capable of firing over 500 miles.
Jackie Brown is a middle-aged airline stewardess who supplements her income by smuggling arms for crime kingpin Ordell Robbie. One day she is caught and the agents offer her a deal in order to apprehend Robbie. Robbie, however, is onto the threat and tries to have Brown eliminated. What follows is a dangerous game of bluff, deceit and betrayal.