Returning from her vacation, Mona talks to Spencer and the two decide to only be friends, not lovers. When she tells Dee Dee that she has learned horseback riding, she learns that Dee Dee still has the horse she got during childhood, which caused some big arguments between the sisters back in the day. Mona then decides to get her own horse, which goes terribly wrong.
Mona and Dee Dee agree to hook each other up on dates, but while Dee Dee looks extensively for a great guy for Mona, Mona puts off the task and then enlists Spencer and Adam to help her out of the jam. Meanwhile, Mona and Phyllis are offered the chance to get in on Dee Dee's mother-daughter photo with Big Dee Dee, but the two ladies try to trump one another with their wardrobes.
Mona tries to sign a deal with a single-mother artist, so she pretends that Drew is her son to help win her over. When that doesn't work out, Mona suggests that the company stop going out of its league and try to sign new artists using a talent search, which soon brings all of her tension with Spencer to a head. Meanwhile, Dee Dee goes crazy trying to build herself a cabinet, while Charles is driven crazy by Big Dee Dee's obsessive smothering.
Mona decides that she and Dee Dee should curtail their meddling when they inadvertently convince their friend Neil's jittery bride to call off their wedding right before the ceremony, but Dee Dee coaxes Mona into letting them take in Neil after the fallout.
Mona's upcoming presentation for Kai on her talent search project has her working lots of overtime, which keeps her out of Dee Dee's parties and out of the know when Phyllis and Ray move in together and Spencer starts seeing someone new.
Dee Dee fumes when she finds out that Mona is hanging out with her rival, Stephanie Seymour, but Mona's attempts to get the two ladies to like one another end with disastrous results. Meanwhile, the talent search finds itself saddled with an applicant who simply won't consider rejection an option.
Kai grudgingly agrees to give Spencer's friend RJ, a singer with talent and a penchant for hard-partying, a chance at a music career, but Spencer soon finds himself going to extraordinary lengths to get RJ to focus on recording. Meanwhile, Big Dee Dee's involvement in Adam's acting preparation creates a longing for her own renewed stage career.
Dee Dee meets her favorite writer at a book signing and sets up a date with him, but while things appear to be progressing nicely, she quickly hesitates on taking things forward when she discovers that his two young daughters live with him full-time. Meanwhile, Phyllis gets irked at Ray's added work schedule at the radio station and soon is at everyone's throats, causing her to try and calm down while staying at Mona's place.
Ray is unable to make the Thorne Thanksgiving dinner, so Spencer invites his mother, who shockingly learns of Spencer's reacquaintance with Ray when Ray manages to show up after all. Meanwhile, Phyllis and Ray split up due to his inability to get over his ex, while Mona convinces Dee Dee to open up about her feelings toward their much-absent father.
Dee Dee finally decides to introduce Carter to everyone after keeping him a secret, at which time Big Dee Dee tries to get Mona to somehow break them up. Not only is Dee Dee angered by the news, she is also shocked by how Carter takes it all in. Meanwhile, Mona and Spencer's new assistant is fun to be around, but has no work ethic whatsoever.
Mona has difficulty carrying on a relationship with a man who, as he informs her, is living out of his luxury car.
Mona stews over the fact that Dee Dee always beats her at things, so she resolves to win big at the poker party Dee Dee is hosting. At the party, Phyllis takes home Big Dee Dee's wedding ring when both uninvited ladies show up to play. Meanwhile, Adam attempts to snag a list of the contents of Spencer's digital music library.
After Kai continues to hog the credit for the Delicious Records Fast Track talent search, Mona is encouraged by the family to seize her rightful credit, but the plan goes very awry when Mona takes their advice. Meanwhile, Big Dee Dee resumes her professional relationship with her acting agent, but her first gig back is a dog commercial in which the dog is the real star.
Dee Dee learns that the co-star of Big Dee Dee's new, self-financed play is engaged to her hero, Maxine Shaw, and tries to get reintroduced to Maxine in order to apologize for an interview gone wrong long ago.
Mona is livid when Spencer potentially ruins Delicious Records' opportunity to land Jimmy Jam and Terry Lewis for their talent search contest. Meanwhile, before she has even begun her new job, Dee Dee has her position cut down which prompts her to show she still can thrive without her father's help.
Mona grows increasingly anxious as she is given more responsibility in selecting the FastTrack contest search winner, but is encouraged by Dee Dee to be more secure with her music industry savvy. Mona then joins Jimmy Jam and Terry Lewis for a workshop, after which time the three manage to select Delicious Records' next signed act.
Mona is shocked when she learns that Dee Dee has unwisely reunited with Carter, but tells her to forget about crying on her shoulder when the reunion inevitably goes sour. Meanwhile, Dee Dee and Big Dee Dee face a hair crisis, while Spencer tries to find fortune in the world of photography.
Mona wishes she hadn't encouraged Dee Dee to stop letting people take advantage of her when Dee Dee decides against doing her a favor.
A major record label attempts to woo Mona away from Delicious, but Mona irks Phyllis when she fails to ask for her advice, opting for the wisdom of her father instead. Meanwhile, Big Dee Dee tries to outshine her friends by giving Drew an extensive and lush birthday party.
Dee Dee gets Mona, Spencer, and Adam to help her out on a charity telethon during Mother's Day, but when Big Dee Dee decides to include herself and becomes unbearable, Phyllis reveals to all that Dee Dee was born out of wedlock, a fact of which Dee Dee was previously unaware. Phyllis' inability to keep a secret also causes some friction between her and Mona.
Dee Dee tries to bond with Phyllis by hooking her up with her divorced professor. When that relationship fails to spark, however, an angry professor alerts the authorities to Phyllis' abundance of cats, which only ends up turning Phyllis against Dee Dee.
Dee Dee is troubled over her lack of job, which makes writing her graduation speech a problem. Mona tries to keep her mother from becoming her neighbor.