Luann tells Dorinda about her wedding plans; Bethenny and her realtor friend seek to sell the apartment; Carole, who is invested in the upcoming presidential election, makes changes to her living situation; Luann confronts Ramona about her meddling.
Tinsley Mortimer moves back to the city; Bethenny invites Carole and Ramona over to discuss life, politics and Sonja's new roommate; Ramona fills Dorinda in on the dirt she has about Luann's fiancé, Tom; Sonja throws a Mad Hatter tea party.
The women head to the Hamptons for a weekend of fun and an early birthday dinner at Ramona's; Carole talks about the election; Dorinda prepares to see Sonja; Ramona takes the wrong approach with Bethenny when asking about her film role.
During Ramona's dinner party, Dorinda confronts Sonja about her incessant trash talking; Carole excludes Ramona from her election night party because she doesn't believe Ramona is taking the presidential election seriously enough.
Carole and her mother go canvassing in Pennsylvania, then Carole and her friends watch the election results come in; Dorinda contrives to get Ramona to her surprise party, but Ramona unknowingly throws a wrench into the plans.
Carole attends the memorial service for Dorinda's late husband; Bethenny weighs moving to a larger apartment; Dorinda and the other bridesmaids get a sneak peek at Luann's wedding dress; Ramona questions Luann about not being invited to her wedding.
Ramona gets advice about her situation with Bethenny; Tinsley, Ramona and Sonja hit the Upper East Side for a night out; Tinsley meets a young suitor; Bethenny meets Luann's fiancé, while Carole learns there may be trouble in paradise.
Bethenny meets with broker Fredrik Eklund to discuss selling the Mercer apartment; Ramona shows Carole a text about Luann's fiancé, Tom; Dorinda invites the women to her home in the Berkshires, where they decide to stage an intervention for Luann.
The women join Dorinda in telling Luann what they've been hearing about Tom; Bethenny urges Luann to get out now; Ramona's weird behavior at dinner throws everyone off; the conflict between Bethenny and Ramona reaches new heights.
Bethenny and Ramona's fight reaches an explosive level; Carole shows Tinsley an available apartment; Luann and Tom host a final pre-wedding lunch with Dorinda and old friends; Carole serves as host of an art opening; Luann and Tom head to Palm Beach.
Bethenny hosts her annual holiday party but doesn't invite Ramona; Luann and Tom get married; Tinsley learns that Frenchie has moved into Sonja's townhouse; Luann and Tom host a New York reception for the friends not invited to the wedding.
Sonja's love triangle gets more complicated; Tinsley goes apartment hunting; Carole and Adam bicker; Fredrik and Bethenny prepare to put her apartment on the market; Carole and Dorinda go to Washington, D.C.; Ramona throws a party at her apartment.
Dorinda fights with Sonja while at lunch in the Bronx; Tinsley breaks down; despite the tension between Ramona and Bethenny, all of the women head to Vermont; Tinsley feels as though the others are ganging up on her in regards to her life decisions.
Sonja digs a deeper grave for herself; while the women hit the slopes, a big news story about Bethenny breaks; Bethenny is on the fence about inviting Ramona to Mexico; the group plays a game of truth or dare, and Dorinda winds up attacking Luann.
Bethenny fine tunes the upcoming trip to Mexico; Carole has her day in court; Sonja gets an intimate cosmetic treatment; Bethenny is forced to face Ramona at Dorinda's dinner party; Tinsley practices her flirting on a blind date set up by Carole.
As the women arrive in Mexico, Ramona and Sonja scramble for the best room, swiftly alienating themselves from the group; Tinsley confronts Ramona and Sonja about a damaging article; Luann takes a tumble; Bethenny reprimands Sonja.
Bethenny confronts Ramona about attending the trip; Tinsley readdresses the article with Sonja; Ramona attempts to buy her way back into Bethenny's good graces; Bethenny takes the ladies on an educational day-drinking trip.
Following their day trip to Tequila, Jalisco, the women drink up and strip down at the villa; Dorinda and Bethenny get into a fight; some of the women head out for a day of fishing and whale watching; Luann flubs the rules of a game.
Tinsley has Carole over to see her new home; Luann and Tom challenge each other during a game of tennis; Bethenny deals with the stresses of renovating a new apartment; Dorinda has John over for a romantic dinner.
Dorinda confronts Sonja over the "Tipsy Girl" allegations; Luann gives an update on her first few months of marriage; Bethenny questions Ramona's attitude toward others; the housewives speculate on Ramona's behavior; Andy Cohen hosts.
Tinsley opens up about her traumatic relationship with her ex-husband; Carole reflects on her political aspirations; Sonja discusses her love triangle, which elicits shocking accusations from Dorinda; Bethenny reveals how she plans to move forward.
The women look back on their fun-filled trip to Mexico, from Luann's fall to the drinking marathon; Bethenny questions the sincerity of Ramona's tearful apology; in the hot seat, Ramona is forced to address the accusations she made against Bethenny.