Mood refers to the emotions a story evokes in the reader; tone refers to the author's attitude about the subject matter that comes through in the writing. Tone will usually remain constant in a story while the mood can change as the plot progresses.
The mood of the story begins with the reader feeling sympathetic toward the Bergerons and then frustrated by the ridiculous "handicaps" that their society forces on smart, beautiful, strong, or talented people. The mood becomes excited and suspenseful when Harrison appears, proclaims himself Emperor, and tears off his handicaps. Readers then become hopeful, and the mood changes to light and joyous during Harrison's dance with the ballerina. However, when Diana Moon Glampers shoots the two "criminals" dead, the mood becomes serious and dark. Readers feel sadness for Hazel, as she has seen the death of her son on live TV but cannot even figure out what happened. Readers may feel angry or hopeless at the end of the story when George and Hazel return to their monotonous daily routine of "equality."
The tone Vonnegut uses in the story is resigned and sardonic. The sentence "It was tragic, all right, but George and Hazel couldn't think about it very hard" shows an acceptance of the society the Bergerons live in. Situations that should provoke outrage are presented calmly. However, the reader can pick up on a sardonic tone; there is a sense of irony and satire behind some of the words. When Vonnegut writes, "Hazel, as a matter of fact, bore a strong resemblance to the Handicapper General, a woman named Diana Moon Glampers," readers understand he is mocking both Hazel and the H-G by that comparison. The vacuous conversation between George and Hazel that occurs at the end, after their 14-year-old son has just been killed, is highly ironic because the couple, or at least the narrator, should be furious about the event.
The mood in the story changes from frustration to hope to anger to despair as the plot unfolds. The tone remains resigned and satirical throughout.