When the man who plays Duffman undergoes hip replacement surgery following an injury during a parade and retires, Duff Beer sets up a reality show presented by Cat Deeley in order to find his replacement. Homer wins the competition, but the Duff owner Howard K. Duff VII tells him that he has inserted him with a chip that will reveal if he drinks, because he must stay sober on the job.
While sober, Homer sees the misery that Duff is causing to the people and environment of Springfield. At a motor racing event, he gives out alcohol-free beer as a placebo in an attempt to convince the audience that alcohol is not essential for a good time. This angers them, and they form an angry mob. Howard K. Duff fires Homer, and tells him that there was no chip, so Homer returns to heavy drinking. Later, Howard K. Duff tracks down the former Duffman who is now working at a coffee shop, and convinces him to take his old job back.