Mona, a self-reliant record executive, is set to move into the penthouse apartment that her father has always promised her. But her plans of getting settled in her new apartment soon come to an end when she learns that her spoiled half sister, Dee Dee, and Dee Dee's overbearing mother also lay claim to the apartment. The sisters' relationship is further strained when Dee Dee inadvertently attracts a man whom Mona was pining for.

Mona's music-video shoot for a rapper may end in disaster when he refuses to leave the dressing room—until he meets Dee Dee. While Mona is pleased with the rapper's newfound enthusiasm for the shoot, she soon begins to worry that he's using Dee Dee.

Dee Dee persuades Mona to attend a banquet that's being held in honor of their father, but the experience reminds Mona that she's the odd one out within her dad's ""new"" family.

Dee Dee is smitten with her new beau, but the romance sours when she learns that he and Mona dated in high school. Although Mona gives her blessing to the union, she soon changes her mind.

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.

Mona and Phyllis attend Thanksgiving dinner at Big Dee Dee's, where Mona's grandmother is the guest of honor. But Dee Dee becomes jealous when she learns the older woman showers Mona with affection. Meanwhile, Phyllis and Big Dee Dee make a deal; and Spencer blurts out one of Mona's secrets to her mother.

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.

When Dee Dee becomes frustrated with Neil because he does not seem interested in getting intimate, he divulges that he is celibate. Meanwhile, Mona is under pressure at work and takes up smoking again, but she is too embarrassed to admit it and tries to hide it from her family.

Spencer thinks that he has gotten a girl pregant and Dee Dee and Mona force him to get an AIDS test.

Mona fears a lonely Valentine's Day, but her tears may be for naught when two men from her (recent) past both ask her on dates. Also, Dee Dee is miffed that Neil would choose work over her. Meanwhile, Big Dee Dee is angry with her husband, who also chooses work over her.

When Mona mistakes a dinner date with a handsome reporter as a personal affair, she unwittingly gets quoted in a music magazine saying disparaging things about one of her music label's artists that ends up getting her fired. Meanwhile, Dee Dee utilizes her law school knowledge to try to get the story retracted.

While Mona struggles to find work after poisoning her reputation in the record industry, the reporter whose article got her fired tries to make amends and sets up a meeting for Mona to plead her case to Big Phat Slim Jim, the artist she disparaged, in hopes of getting her old job back. Meanwhile, Mona's family and friends offer their encouragement and support in their own special ways during her difficult job search.

In a strange reversal of fortunes, Dee Dee's charmed life seems to hit an unlucky streak at every turn while, ironically, the usually pessimistic Mona's life becomes auspicious from one moment to the next. When Dee Dee starts doubting herself after failing her assigned mock-court competition at school, with Mona's help she manages to regain her waning confidence by confronting a crooked businessman.

Mona dates a hunk whose looks almost compensate for his lack of brains. As a result, she tries to hide him from her friends and family, but the effort is for naught when they're invited to her father's dinner party for a U.S. senator.

Mona drags Dee Dee to a self-defense class, where she accidentally hurts her little sister while practicing a back flip. Overwhelmed with guilt, she waits on Dee Dee hand and foot, unaware that Dee Dee's milking the injury.

Mona becomes antsy about her friendship with Spencer after she has a romantic dream about him. Meanwhile, Dee Dee---who thinks the dream was about a woman---introduces Mona to a lesbian friend of hers.

When Mona has Spencer masquerade as her beau at a friend's wedding, Spencer realizes that he has romantic feelings for her, and has had them since college. Meanwhile, Dee Dee dumps her boyfriend when she learns he has matrimony on the mind.

For Mother's Day weekend, Big Dee Dee and Dee Dee vacation at an exclusive spa. Not to be outdone, Phyllis and Mona do the same, and end up in the room next door. The weekend quickly goes from weird to worse when Dee Dee blurts out that she wishes her mom was more like Phyllis.

The gals' already tenuous friendship spirals toward dissolution when Dee Dee celebrates the end of her school year by hosting a raucous celebration that keeps Mona awake all night. Things get worse when Dee Dee installs a hot tub, which floods Mona's apartment. Stepping in to mediate, their father, Charles, reminds them that ""like it or not, we're family."" But the squabbling continues, until a medical emergency involving their dad arises.

Mona returns from a Hawaiian vacation and clears the air with Spencer. They reaffirm their decision to just be friends. While looking through some vacation photos with her family, Mona reveals that she can now ride a horse. She is stunned to learn that Dee Dee still has the horse their father gave her as a child, Daddy's Favorite, and that she has lied for years about having not kept the horse. (The horse led to a major rift between Charles and Phyllis that separated the sisters for a decade.) Mona decides to buy her own horse, but it doesn't quite go as planned. Meanwhile, Adam helps Spencer uncover the cause of Kai's sudden unpleasant attitude toward him.

Mona and Dee Dee agree to get each other dates as a birthday present. Dee Dee does some thorough research and finds Mona a seemingly perfect guy, James, and the two get along well enough to set up a second date. Mona waits until the last minute to begin her search and is forced to turn to a less-than-helpful Spencer and Adam as she tries desperately to track down someone for her sister. Meanwhile, Dee Dee convinces a reluctant Big Dee Dee to let Mona and Phyllis join them for a mother/daughter portrait sitting. Big Dee Dee and Phyllis see the photograph as another opportunity to outdo each other and go all out to find the flashiest outfits possible.

Mona pretends that Drew is her son in the hopes of winning over an artist that she is trying to sign who is a single mother. After her plan fails miserably, she suggests that Delicious stop chasing after artists that they have no chance of signing and instead conduct a talent search. Spencer continually bad-mouths all of Mona's ideas, and the two snipe at each other. Adam advises Spencer to finally deal with the tension between Mona and him before it destroys their friendship. Meanwhile, Dee Dee obsesses over trying to build a cabinet without any assistance; and Big Dee Dee drives Charles crazy when she tries to get over her depression by scheduling lots of ""quality time"" for them as a couple.

Mona and Dee Dee attend Neil's wedding, where their conversation with the already-nervous bride in the bathroom leads her to call off the wedding. Mona believes they should stay out of the situation to avoid causing further harm; but Dee Dee insists on taking in the devastated Neil when he shows up on her doorstep. Spencer regrets giving an overly generous tip to the stripper at Neil's bachelor party, and tries to get the woman to return it. Meanwhile, Big Dee Dee fears that she and Phyllis may actually have things in common after they run into each other at a funeral and discover that they both dated the deceased.

Mona must work long hours as she prepares a major presentation for Kai about her talent search idea. She begins to lose touch with her family and friends, as she misses out on Dee Dee's weekly parties and is unaware of major news like Spencer getting a new girlfriend and Phyllis and Ray deciding to live together. Mona makes an effort to better balance her personal and professional lives, with disastrous results. Meanwhile, Adam, upset that being gay is no longer the ""in"" thing, decides that he is going to be straight.

Dee Dee is furious to discover that Mona has become friends with Dee Dee's rival, Stephanie Seymour, after meeting her through a work event. Dee Dee insists that Mona should dislike the same people that she does because it is her duty as a sister. Mona tricks the duo into having tea with her in the hopes of getting them to make peace, but things do not exactly go the way she had planned. Meanwhile, a rejected applicant for the talent search refuses to take no for an answer.