Originally Aired: March 9, 1958

In Gunsmoke #309, "Laughing Gas," a traveling entertainment show comes to Dodge City, promising amazing hilarity through the effects of nitrous oxide. Chester eagerly anticipates the show after borrowing twenty-five cents from Marshal Matt Dillon, despite Doc Adams' warnings about the dangers of the intoxicating anesthetic. The evening takes a violent turn when Cloud Marsh volunteers to take the gas and becomes belligerent on stage, threatening to fight everyone in the room before breaking down in tears and destroying the equipment. His humiliation in front of the whole town sets the stage for deadly revenge.

The next morning brings worse news when Mrs. Stafford frantically summons Doc Adams after her husband Earl is brutally beaten behind their store by Cloud Marsh and his two brothers. As Doc tends to the unconscious showman, Marshal Dillon reveals he knows Earl Stafford's real identity—he's actually Ernie Stubblefield, a former gunfighter from the Red River with four killings to his name and prison time behind him. Now Mrs. Stafford faces an agonizing choice: seek justice for her husband's beating or protect the peaceful new life they've built by avoiding trouble with the vengeful Marsh family.