In an attempt to win Mona's respect and stop living off her father's largesse, Dee Dee takes a job as a waitress. Meanwhile, Phyllis persuades Mona to give a video-dating service a try.

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.

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.

After Dee Dee loses her old room to the baby and Big Dee Dee misses several appointments, Dee Dee begins to worry that the baby is forcing her out of her parents' life. She suffers from so much stress that she has a breakdown and hears a doll talking to her. Mona recommends that she make an appointment with Phyllis to discuss her problem. She says that she feels as though she is the only one who is worried about the way the baby will change her life. Phyllis assures her that her reaction is perfectly natural and that she should air her concerns with Big Dee Dee. Before she gets around to it, Big Dee Dee admits to her own anxieties about the child's birth, and thanks Dee Dee for her support. The conversation reassures Dee Dee about her importance in her mother's life. Meanwhile, Spencer continually cancels on Mona because of plans with Camille. She looks to Adam to take his place, but Adam isn't too thrilled about this.

Dee Dee's cousin Barbara comes to town for Big Dee Dee's baby shower, and stays with Mona because there is no room at Dee Dee's place. Mona is furious to learn from Barbara that Dee Dee shared things that Mona had told her in confidence about the effect her mother's bitterness has had on her feelings about marriage. Mona gives Dee Dee the silent treatment, but later has a talk with Phyllis about her fears. Big Dee Dee dreads the shower because she knows the guests will insist on touching her belly. Meanwhile, Spencer gets a makeover from Adam and some friends in the hopes of impressing Camille's social crowd.

With Drew's christening approaching, Mona and Dee Dee vie for the right to be their brother's godmother. They grow increasingly competitive as they buy him gifts and try to impress Charles and Big Dee Dee. While driving home from a shopping trip, Dee Dee takes a cheap shot at Mona when she brings up the fact that she is only Drew's half-sister. Big Dee Dee is appalled by this statement and urges Dee Dee to apologize to Mona as soon as possible. Meanwhile, Phyllis tags along to church with Mona and Spencer and begins making a play for the handsome widowed pastor. She soon finds some unexpected competition in the form of a very forceful church member who is just as determined to make the pastor her man.

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 tries to comfort Dee Dee after Carter appears on a talk show and says that he is seeing someone. When she later discovers that Dee Dee and Carter have secretly reunited, an angry Mona declares that she will not help Dee Dee pick up the pieces after the new ""casual"" relationship fails. Meanwhile, Spencer tries to get into photography in the hopes of getting rich; and Dee Dee and Big Dee Dee face a crisis involving their hair stylist.

Dee Dee has difficulty finding a job after graduation. After she announces plans to return to school, her fed-up father not only cuts her off, but orders her to pay back all expenses accrued since her 21st birthday. Mona begins dating her handsome and charming new neighbor, Lorenzo, but her insecurities stand in the way of the relationship. Spencer changes his wardrobe in the hopes of getting people to take him more seriously.

Mona realizes that she needs to slow down her relationship with Chase after they start spending so much time having sex that it begins to affect her job and other aspects of her life. Dee Dee plans a "legends ball" on behalf of her mother (who is depressed because of her floundering acting career), but finds that none of the invited guests want to attend. Spencer buys a gigantic new truck that soon leaves him financially strapped because he can't afford gas.