It's the Mertzes' eighteenth wedding anniversary. Ethel longs to celebrate it by going to the Copacabana, while Fred wants to attend the fights. As can be guessed, an argument soon ensues among the couples. Ethel and Lucy decide that they will go to the club-with dates! Now, this is perfectly fine with Fred, but Ricky is worried. So he and Fred call an old friend, Ginny Jones, for dates so that they can go to the nightclub and spy on their wives. Coincidentally, Lucy and Ethel have also called Ginny about getting dates to go to the club. When Ginny tells the girls about the boys' plans, Lucy decides that she and Ethel will impersonate the boys' blind dates. Thus, the two of them enter the Ricardo apartment decked out like country bumpkins, which makes for some superb Lucille Ball schtick.

To her dismay, Lucy finds out that she's put on 22 pounds since marrying Ricky. Complications arise when one of the girls in Ricky's new show quits, making a vacancy for a dancer who can wear a size twelve costume. At the auditions the next morning, Lucy tricks Ricky into saying that if she loses enough weight (12 pounds) in four days, then she can be in the show. Thus, she starves and exercises, with Ethel as her coach. In one funny scene, she tries to steal food from the Mertzes' dog Butch, because she is so hungry! She finally resorts to using a steam cabinet, and manages to get down to the required 120 pounds. At the end, Lucy and Ricky perform "Cuban Pete/Sally Sweet." She's a hit, but at the end she collapses, suffering from malnutrition.