An 18-year-old boy who grew up in a slum was sued in court on suspicion of killing his father. Twelve people of different professions formed a jury in this case, and they had to reach an agreement in the break room to decide whether the teenager was guilty or not, and if convicted, the juvenile would be sentenced to death. The twelve members of the jury are different, with the exception of juror No. 8 (H enry Fonda), who dismisses the case where the facts of the crime are so clear that the juvenile is found guilty before the discussion begins. Juror No. 8 raised his own "reasonable doubt" and patiently convinced the other jurors that their different outlook on life was also in conflict and contest in the process.