Jim Terrier (Sean Penn) is a former special forces soldier who, in his 50s, has become a black-ops mercenary. He is part of a team deployed by a corporation in the Democratic Republic of Congo in 2006, under the cover of providing security to local projects. He falls in love with Annie (Jasmine Trinca), a fellow expat working as an NGO doctor in a local hospital. During this period, even though civil war has wreaked havoc on the country, large multinational mining companies continue to profit from the country's mining industry. After the Minister of Mining announces his plans to declare contracts with the mining companies unjust and renegotiate the terms, the mining companies hire Terrier's team to assassinate the Minister to ensure their access to the rich mineral resources. Terrier delivers the fatal shot from a sniper rifle and flees from Africa, leaving Annie behind. After that, Terrier retires from his mercenary career.
Eight years later he returns to DRC as a charity worker to build wells. One day Terrier is brutally assaulted by a local hit squad, but he manages to kill them all. While searching the attackers' bodies, he finds signs that the attack was not random and that he was the target. Scared and suspicious, Terrier flees to London to meet an ex-mercenary colleague, who reveals that Cox, their ex-boss in the Congo assassination, has formed a large international security firm offering its services to major clients, such as the Pentagon. The firm's head wants to eliminate all of the former members of the assassination squad as revelations of their former activities could hinder the development of the new firm. Now the firm's hit teams chase Terrier around the clock, meanwhile killing his friends and kidnapping Annie.
However, Terrier still keeps highly compromising materials that can reveal Cox's role in the Congo assassination and uses it to lure Cox and his team to a bullfight in Spain, threatening to expose their complicity unless they trade Annie for the evidence. Unknown to them, Terrier makes a deal with Interpol to provide evidence to aid their ongoing investigation. Despite battling severe head trauma suffered from his violent past, Terrier defeats the experienced mercenaries sent to kill him. As he struggles to help Annie escape to safety, Cox discovers them. Terrier is wounded but manages to shoot Cox, who is then gored by a loose bull. Interpol officers arrive and take Terrier into custody, though Agent Barnes promises to do what he can to help Terrier avoid doing more jail time than necessary.
The film ends with Terrier, recovered and released from prison, reuniting with Annie in the DRC.Sean Penn as Jim Terrier
Jasmine Trinca as Annie
Javier Bardem as Felix
Ray Winstone as Stanley
Mark Rylance as Cox
Idris Elba as Jackie Barnes
Peter Franzén as Reiniger
Billy Billingham as Reed
Daniel Adegboyega as Bryson
Ade Oyefeso as Eugene
Circa January 2013, French action director Pierre Morel (Taken) entered negotiations to direct Sean Penn in Prone Gunman, an action thriller being produced by Silver Pictures’ Joel Silver and Andrew Rona. The film is based on the 1981 novel The Prone Gunman by French crime novelist Jean-Patrick Manchette. The project, from Silver Pictures, was fully financed by StudioCanal, who sold out rights to the film at the 2013 Cannes Film Festival.
In May 2013, Deadline.com reported that Javier Bardem would play a villain. In June, Deadline stated that Ray Winstone had just joined the project. He played a mentor of the hitman (Penn), who is betrayed and then hunted by the organization he worked for. Italian Jasmine Trinca became the female lead. Bardem played Trinca’s husband, and Elba played a mysterious operative named Dupont.
On May 8, 2014, Open Road Films acquired the US distribution rights to the film.
Principal photography took place in the spring of 2013 in several locales across Europe.
The Gunman grossed $10.7 million in the United States and Canada and $13.5 million in other territories for a worldwide total of $24.2 million, against a production budget of $40 million.
The film grossed $5 million in its opening weekend, finishing at 4th at the box office.
The review aggregator website Rotten Tomatoes gave the film an approval rating of 17% based on 145 reviews, with a rating average of 4.4/10. The site's critical consensus reads, "With an uninspired plot and rote set pieces that are overshadowed by its star's physique, The Gunman proves a muddled misfire in the rapidly aging Over-50 Action Hero genre." On Metacritic, which assigns a normalized rating, the film has a score of 39 out of 100, based on 41 critics, indicating "generally unfavorable reviews". According to CinemaScore, audiences gave the film a grade of "B−" on an A+ to F scale.