Jerry, George and Kramer play basketball with Jimmy, a man who always refers to himself in the third person. George partners with him on selling special training shoes which improve vertical leap, using Jimmy as the spokesmodel. At a New York Yankees meeting Mr. Wilhelm discusses a series of escalating thefts, believed to be an inside job. George is sweating heavily as a result of exercising, causing him to look suspicious. At a dental appointment with Dr. Tim Whatley, Jerry sees Penthouse magazines in the waiting room, and learns that the office has a new "adults-only policy".
Elaine has tickets to a benefit for Able Mentally Challenged Adults (AMCA) featuring famous crooner Mel Tormé, and contemplates asking out a blond guy from her health club. At the health club she ends up talking with Jimmy, and agrees to a date with him, not realizing that by "Jimmy" he means himself and not the blond man.
Because of novocaine he was given for dental surgery, Kramer speaks awkwardly and drools water on the health club floor. Jimmy slips in the puddle, injuring his leg, and promises revenge. Without Jimmy, George fails to demonstrate the value of the training shoes to employees at a sneaker store, as his vertical leap is embarrassingly short. Kramer shares a taxicab with an executive at the AMCA, who mistakes him for a mentally handicapped adult due to his novocaine-induced slurring and training shoes, and invites him to the event as the guest of honor. Jerry and Elaine recognize the misunderstanding but are not overly concerned that Kramer's cover will be blown.
At a second appointment with Dr. Whatley, Jerry is put to sleep with nitrous oxide. Whatley tells Jerry that his regular assistant Jennifer is at Dr. Sussman's office and has been replaced by Cheryl, because "we find it fun to swap now and then." When Jerry wakes, he sees Whatley and Cheryl adjusting their clothes and fears he was sexually violated while asleep. Kramer later picks up a copy of Penthouse and reads an anonymous letter from a dentist who says he recently "had a little fun" with his dental hygienist and one of his patients. Jerry looks on in shock.
Mr. Wilhelm walks in while George is on the phone with Sports Wholesalers talking about "beautiful athletic gear" (the shoes) and sweating from the Kung Pao chicken he ate for lunch. Wilhelm becomes convinced George stole the equipment and reports him to the team owner, George Steinbrenner. The stress makes George start talking in the third person; this confuses Steinbrenner, who ends up talking about his lunch and completely forgetting about the stolen equipment.
After Jerry tells Elaine about Jimmy referring to himself in the third person, she realizes her mistake. However, finding Jimmy's manner of speech charming, and additionally learning that the man she was initially interested in is gay, she decides to keep the date. At the benefit, Jimmy attacks Kramer, slugging him in the face before being dragged out by security. Kramer's lip becomes swollen and he once again looks and speaks as if he were mentally handicapped. Mel Tormé dedicates a rendition of "When You're Smiling" to a beaming Kramer.