Reginald Rose's play 12 Angry Men, sometimes known as 12 Angry Jurors so as to include females in the cast, opens with the voice of the judge announcing the charge of murder in the first degree. He tells the jury that they must come to a unanimous verdict before the clerk dismisses them to the room where the entire play takes place. Some versions of the play include jurors smoking, but each one enters and looks around. Juror seven takes out a pack of gum and offers it to others. Seven notices that the room is hot due to the lack of air conditioning. Once they are all inside, the guard locks them in. Juror three complains that the six days of the trial were about four days too many. Juror ten has a cold and blows his nose. The Foreman asks all the jurors to take their seats. Juror seven mentions that he has tickets to see a play that night, so he hopes it will go quickly.

The jurors are surprised that a child would kill his own father. The Foreman asks if they would like to discuss the case first or just start with a vote; they say vote. When he asks who thinks the kid is guilty, eleven hands slowly go up. Juror eight says he is not sure. Juror eight feels sorry for this nineteen-year-old boy whose mother died when he was nine and has lived a rough life. He wants to talk about the case a bit before he votes to send this boy off to die.

Twelve suggests that each man explain to Juror eight why they are voting guilty. Three starts with the testimony of the man who lived beneath the apartment where the murder occurred. He heard loud noises then heard the son say, "I'm gonna kill you" before he heard a thud and saw the kid run away, which is when he called the police. They found the father with a knife in his chest. The coroner determined the time of death to be around midnight. The boy had claimed he was at the movies during that time, but he couldn't remember what movie he saw. Then ten adds the testimony of the woman across the street who said she looked out her window past the el tracks and saw the son stick the knife into his father.

Six adds the testimony of the people across the hall who heard the father and son arguing earlier that night. They heard the father hit the son. Juror seven talks about the child's past, which included reform school, being arrested for mugging, and being picked up for knife fighting. He stabbed a boy in the arm. The other jurors start chiming in about what a bad neighborhood the accused lived in when juror five mentions that he lived in a slum all his life. He feels as though they are personally attacking him.

Juror three refocuses them on the evidence, pointing out that the boy admitted to buying a switch-knife. Juror eight suggests they ask the guard to bring it in for them to look at. The boy had bought it that evening and the storekeeper said it was one of a kind. The boy said it was a present for a friend, and then on his way home he somehow lost it. The guard brings in the knife, which Four takes and stabs into the table. Eight reaches into his pocket and stabs a similar knife right next to it. Eight said he bought it the previous night at a junk shop near the boy's house. Eight goes around the room asking the jurors if they think the boy lied, and most of them admit that they do. Eight then asks that they call for another vote. He won't vote, and if there are still eleven votes for guilty, they can take in the verdict. Everyone agrees. The Foreman hands out ballot slips as the lights fade to end the act.