In Twelve Angry Men, a drama about a jury deliberating over a murder case, the initial vote taken is eleven "guilty" and one "not guilty." The rising action progresses as more and more jurors are won over to the "not guilty" verdict as they experience reasonable doubts about whether the accused boy killed his father. The most vociferous proponent of the "guilty" verdict is Juror 3, a businessman who is aggressive and opinionated. We also find out through some personal conversation he has with one of the jurors that he has a son of his own who is about the same age as the accused but that he has not seen his son for three years. He shares how he had taunted his son for not standing up in a fight, but later the boy fought with him and punched him in the face. They never reconciled.
Juror 8 picks up on the fact that Juror 3 seems to have some personal vendetta against the accused boy. Trying to get a rise out of Juror 3 to prove a point, Juror 8 baits him by saying he wants to be the boy's executioner and calls him a sadist. This causes Juror 3 to lunge at Juror 8 and shout, "I'll kill you!" Juror 3 has previously argued that when the accused allegedly shouted those same words at his father, he must have meant it, because anyone who says such a thing means it. Now he must admit that he didn't really mean his own threat aimed at Juror 3.
Later Juror 3 says the whole case rests on the woman who claimed to be an eyewitness. He says all the other evidence could be thrown out and the case would still stand based on her testimony alone. When the jurors realize that the woman was nearsighted and could not have seen what she claims to have seen, the other remaining holdouts for the "guilty" verdict, Jurors 4 and 10, change their votes to "not guilty," leaving Juror 3 as the lone vote for "guilty."
In the movie, the man tries to defend his decision and reaches for notes from the trial from his wallet. When he pulls them out, a photograph of his estranged son falls out as well. The man tears up the photograph in a rage, and then breaks down sobbing, saying, "Not guilty! Not guilty!" This reveals that his real reason for wanting to condemn the accused boy was personal and related to his feelings toward his own son. The doubts about the evidence against the boy, the pressure of the other eleven jurors, and perhaps an ultimate understanding of his own motivations combine to make him change his vote to "not guilty."