Mary coerces Matt into asking his friend Brian (guest-star Jason Behr) to take her out on a date despite his lack of interest in her. Although, things begin to heat up between the two kids while on the date---but ultimately ends in disaster after Mary finds out the truth. Meanwhile, Lucy is invited to a sleepover of popular girls, but Lucy is unaware of the group's real intentions for inviting her. Also, Simon begins to teach Ruthie how to swim without taking lessons. Lastly, Eric becomes convinced he's fat and thinks he's getting away with cheating on his diet.