Drafted as a thriller with a love triangle thrown in, "The Gunman" is the tale of an ex-assassin in hiding, who is now being hunted.
In a brief prologue dated 2006, the film opens in Kinshasa in the Congo. A news bulletin reveals how large corporations were seeking control of the natural resources in poor and impoverished countries.
During that phase, in what was referred to as Project Calgary, Jim Terrier (Sean Penn) working for the corporate, assassinates the mining minister of Congo. Then, on the advice of his best friend and partner in crime Felix (Javier Bardem), he leaves behind his girl-friend Annie (Jasmine Trinca) and flees the country.