The drama depicts a jury forced to reconsider its nearly unanimous decision by the single dissenter who sows a seed of reasonable doubt. The story begins after closing arguments have been presented in a homicide case, as the judge is giving his instructions to the jury. As in any American criminal case, the twelve men must unanimously decide on a verdict of 'guilty' or 'not guilty'. (In the American justice system, failure to reach a unanimous verdict, a so-called "hung jury", results in a mistrial.) The case at bar pertains to whether the young man murdered his own father. The jury is further instructed that a guilty verdict will be accompanied by a mandatory death sentence (something that could not happen in the current American legal system). These twelve then move to the jury room, where they begin to become acquainted with the personalities of their peers. Throughout their deliberation, not a single juror calls another by his name because the names are unknown by the jurors.