Plot summary
Peter is smitten when Jan brings home her pretty classmate Kerry Hathaway ( Kym Karath ). Peter is shy with Kerry, so he enlists Greg to help with what to say to Kerry. Kerry mistakenly concludes that Greg is the one interested in her, which causes friction between Greg and Peter. To make it up to Peter, Greg enlists Marcia's help in a play-act to convince Kerry that he is an aggressive, womanizing playboy so she will lose interest in him. Peter arrives home and, unaware of the plan, tells Kerry that "Debbie" (Marcia) is their sister, and that it was an act. Peter's honesty wins Kerry's love.
Credits
Adapted from Wikipedia contributors, List of The Brady Bunch episodes. HTML formatting and reference markers removed.