Marcy wants the Bundys to stay indoors because her "identical" cousin Mandy is coming for a visit and Marcy doesn't want her to be repulsed by them. Mandy's flight, however, is early and she takes a cab. Since the D'Arcys are at the airport waiting for her, she comes to the Bundys. This leads to Mandy spending the day out with Al and Jefferson. Suddenly Peg and Marcy find themselves jealous.