Dee Dee invites Mona to a ""girls night"" with her friends, but Mona instantly feels out of place amidst the ritzy women. When Dee Dee gives Mona an expensive purse, Mona deduces that her half-sister is trying to make her over. Meanwhile, Spencer is attracted to one of Dee Dee's friends.

When Mona and Dee Dee set Spencer up on blind date with a woman they met from the gym, Spencer falls for her hard and fast. But when Mona finds out the girl is only using Spencer to get back at her ex, she tries to warn him -- only he thinks Mona is jealous.