A 19-year-old man has just stood trial for the fatal stabbing of his father. "He doesn't stand a chance," mutters the guard as the 12 jurors are taken into the bleak jury room. It looks like an open-and-shut case—until one of the jurors begins opening the others' eyes to the facts. "This is a remarkable thing about democracy," says one juror, "that we are notified by mail to come down to this place—and decide on the guilt or innocence of a man; of a man we have not known before. We have nothing to gain or lose by our verdict. We should not make it a personal thing." But personal it does become, with each juror revealing his own character as the various testimonies are re-examined, the murder is re-enacted and a new murder threat is born before their eyes! Tempers get short, arguments grow heated, and the jurors become 12 angry men.