During homecoming weekend at Midwestern University, English professor Tommy Turner and his wife Ellen host a cocktail party for Dean Frederick Damon and his wife Blanche; anti-intellectual trustee Ed Keller and his wife Myrtle; and former football hero Joe Ferguson. Just before dinner, Damon informs Tommy and Ellen that student Michael Barnes, a boyfriend of Ellen's sister, Patricia Stanley, has written an editorial excoriating the trustees as fascists and pointing to Tommy as the only professor interested in freedom of speech. In the editorial, Michael mentions that the following Monday during class, Tommy will read a letter by Bartolomeo Vanzetti, an anarchist executed for murder along with his associate, Nicola Sacco, in 1927. Both Damon and Ellen are worried that if Tommy goes ahead with his plans, the trustees will brand him a Communist and fire him. Tommy does not want to be an example, but does not really understand why he should not read the letter to his class. Later Joe, a former boyfriend of Ellen's, arrives with flowers for Ellen's birthday, which Tommy has forgotten, and announces that he and his wife are divorcing. During cocktails, Keller learns about the Vanzetti letter and expresses his horror that Tommy would expose his students to something un-American. Tommy gets so angry at Keller that he decides to read the letter to spite him. Then when Joe and Ellen dance together to an old song, all of Tommy's old jealousy of Joe returns. After the rally, Joe offers to take Tommy and Ellen to dinner, but Tommy pleads illness and encourages Ellen to accept his offer. The next day, the entire campus is in an uproar over Michael's editorial, and Tommy, believing that Ellen is still in love with Joe, decides to drive her away for her own good. Although Joe does not really want to marry Ellen--he is more interested in who will win the football game--he feels obligated to accept her if she leaves Tommy. While Joe and Ellen attend the game, Tommy and Michael get drunk. In nature, Tommy says, if another male threatens to take away an animal's mate, he tears him apart. Tommy then points out that he is a male animal. When Ellen and Joe return from the game, which was won by Midwestern at the last moment, Tommy announces his intention to knock Joe out. On Monday morning, Tommy, having been knocked out by Joe, must face the entire university and read Vanzetti's letter. Before they leave, Ellen announces her plans to live with Joe, upsetting both Joe and Tommy. Keller, meanwhile, has expelled Michael and threatens Tommy with dismissal if he reads the letter, but to everyone's surprise, Damon defends Tommy. In front of an enormous crowd, Tommy gives an impassioned speech in favor of the free exchange of ideas and free speech and then reads Vanzetti's moving and non-political letter. Ellen is deeply impressed by her husband's behavior, as are the students. Tommy is given a hero's reception and is reconciled with Ellen. Free from his obligation to Ellen, Joe plans to return to his wife.