The Gunman (2015)

Eight years after fleeing the Congo following his assassination of that country's minister of mining, former assassin Jim Terrier (Sean Penn) is back, suffering from PTSD and digging wells to atone for his violent past. After an attempt is made on his life, Terrier flies to London to find out who wants him dead -- and why. Terrier's search leads him to a reunion with Annie (Jasmine Trinca), a woman he once loved, who is now married to an oily businessman (Javier Bardem) with dealings in Africa.