Set in the late 50's, 12 men retire to a jury room to consider the fate of a 16 year old accused of murdering his father. If found guilty he will receive a mandatory death sentence.
The jury is told they must come up with a unanimous verdict and 11 of the jury vote guilty on the first ballot. Juror #8 feels he cannot vote guilty because he has reasonable doubts about the facts of the case. "Suppose we're wrong..." he says.
Together they bitterly struggle with each other becoming twelve angry men, arguing for hours about: the murder weapon, the angle of the stab wound, the testimony of the eye witnesses, and the emotion and prejudices of the individual jurors, until all are convinced there is reasonable doubt.