Twelve Angry Men takes place in the jury room of a courthouse in New York City. The courthouse is not air-conditioned and it is mid-summer. Furniture in the room is basic - a long table and twelve unpadded wooden chairs. The jurors are assigned with making a ruling of guilt or innocence in a first-degree murder case. The verdict must be unanimous.

The jury has already spent time listening to the trial in the hot, confined space of the courtroom and now it faces the prospect of more time in a humid, heated, closed-in space during the decision-making process of the trial. Some of the jurors are tired of being stuck indoors in the heat; some are fed up with the company of other jurors and favor any action that will allow them to finish their jury duty; some are physically uncomfortable with the courthouse furniture and spend time pacing or squirming in an attempt to get relief.