1979. Donald Lavoie is a fearsome hitman who works under the orders of Claude Dubois, the boss of the Montreal South-West mob. The assassin takes under his wing the young rookie Serge Rivard, a hotheaded small-time crook who soon compromises him in a dirty double murder. Thanks to the lawyers dearly paid by the Dubois clan, Donald escapes justice but that's only a temporary setback for Detective Sergeant Roger Burns, who tries to tries to convince Lavoie to become an informer. To test his killer's devotion, Dubois asks him to eliminate someone close to him. When he disobeys the order, Donald joins forces with other criminals to plan a bank robbery to finance his exile to the South. Hunted by the Dubois clan on one side and Burns' investigators on the other, Donald finds himself caught in a tightening vise.