12 Angry Men (1957)

The argument starts before the credits: is Juror 8 a hero of reasonable doubt, or simply the most persuasive man in the room? Sidney Lumet keeps almost the whole story inside one jury room, and Henry Fonda's calm refusal to vote guilty without a discussion turns a murder trial into a study of prejudice, impatience and how groups change their minds. It is the ideal opener for a new club, because everyone will have a view on which juror they would have been.