John Q Archibald (Denzel Washington) is a Chicago factory worker struggling to make ends meet. When his son Michael is rushed to hospital after having a seizure at a baseball game, the doctors say the boy must receive a heart transplant as soon as possible. Lacking the necessary health insurance to cover the operation, John has no choice but to take the chief surgeon hostage, barricade himself in the emergency room, and demand that his son's name be put on a donor-recipient list. As the police gather outside and hostage negotiator Frank Grimes (Robert Duvall) attempts to diffuse the situation, the media begin an in-depth coverage of the siege and in the process turn John into a modern-day folk hero.