Moose watches a report on Floyd's Comet, an astronomical event that supposedly resulted in strange things happening. Pepper Ann and Lydia return home and complain about their respective days and how the other has it easier. As they argue with each other, the comet passes by and the lights go out, with them deciding to go to bed early. In the morning, Pepper Ann and Lydia are shocked to discover that they switched bodies. Moose gets to work at trying to revert them back to normal by having them wish themselves back, but nothing happens. The two of them realize they need to pass themselves off as each other.
Lydia, as Pepper Ann, meets up with Milo and Nicky and upon learning the former's predicament, gives him actual thoughtful advice that helps him. Upon arriving at school, Lydia puts up with the tests, sports and lab experiments, of which she is terrible at and result in big mistakes. Pepper Ann, as Lydia, tries to drive, which she actually cannot do because her license expired, but cannot pull out of the driveway and rollerblades to work. She has difficulty interacting with the customers, cannot work the cash register and is terrible at handling the mannequins.
Lydia and Pepper Ann refuse to acknowledge each other's misery and demand that Moose help them out, which she tries doing through a variety of tropes. They continue their experiences for the next couple of days, until both are invited by their respective dates to attend different outings. Just as the two of them are about to finally admit defeat, Janie takes "Lydia" away to renew her driver's license while "Pepper Ann" is called away by Nicky to challenge Alice Kane to a roller blading competition high up in Hazelnut.
Pepper Ann attempts to reschedule the drive, but accidentally goes in reverse as the instructor loses his glasses. Lydia exclaims how she is not as agile as her daughter and rolls down the hill backwards. Just as they are in the throes of their conflicts, they exclaim how they will never take each other for granted and suddenly return to their original bodies. They manage to meet up with each other with Pepper Ann crowned as the winner of the competition and once again gives bad advice to Milo. Pepper Ann and Lydia return home, wondering what turned them back, only to discover that Moose and Steve the Cat switched bodies.
- Kathleen Wilhoite as Pepper Ann Pearson
- Jeff Bennett as Dieter Liederhosen, Craig Bean, Bernie Guberstein, Mitch, Shelf McClain
- Danny Cooksey as Milo Kamalani
- Clea Lewis as Nicky Little
- Pamela Adlon as Moose Pearson, Woman Customer #1, Steve the Cat, Skull
- April Winchell as Lydia Pearson, Sherrie Spleen
- Don Lake as Sherman Finky, DMV Man, Newstand Owner
- Susan Tolsky as Janie Diggety, Woman Astronomer
- Lauren Tom as Alice Kane, Woman with Baby Carriage
"Ooh, a bicentennial quarter!"
- As stated above, the episode is a take on Freaky Friday with Moose mentioning the similarly named Trippy Tuesday.
- Moose mentions a movie called Large, a parody of Big.