Relaxing after overeating at dinner, the discussion leads to weight gain. Lucy claims that she's the same weight she was when she was married, 110 pounds, but when she gets on the scale, it reads 132 pounds. Ricky and the Mertzes tease Lucy while she cries. Jerry, Ricky's agent, calls to inform him that he needs a new size 12 dancer for his show. Of course, Lucy wants the job. After being worn down, Ricky agrees to let Lucy audition just like everyone else.
At the audition, Lucy is intimidated because the other dancers are younger, prettier, and more scantily clad. Ricky picks Lucy even though she can't do a simple time step. When Lucy puts the costume on, it splits at the seams. She makes him agree to the condition that if she can lose enough weight to fit into the costume by show time, she can have the part.
In her determination to lose weight, Lucy exercises, eats very little, wrestles for food from Butch (the Mertzes dog), and even spends five hours in a pressure cooker box. Lucy loses the weight and is a big success dancing with Ricky. After the show, she's wheeled away on a stretcher because of malnutrition. As she's wheeled away, she hands Ethel a set of keys that open a closet door. In the broom closet is the real dancer, bound and gagged, which Ricky had hired.