Harry, Lucy and Kim go to see Frankie Avalon perform at a nightclub, and Kim is invited on stage to do a duet with Frankie.
Kim gets an invitation to appear in the club's amateur contest later in the week. Lucy schemes to get Avalon to play Sonny Bono to Kim's Cher for the competition.
Special Notes: Frankie Avalon and Lucie Arnaz actually went to a Sonny and Cher show the week before they shot this episode in order to get pointers. Cher lent her the wig, the earrings and the eyelashes for the performance. Frankie and Lucie sang to a prerecorded track.