It's been one crazy summer for the New York City housewives. Bethenny struggles with the sudden passing of her boyfriend Dennis, while Luann is coming to terms with the fact that she relapsed and had to go back to rehab. Ramona is tackling her fear of the water by taking swim lessons, and Sonja is adjusting to her new apartment. Dorinda has made positive changes in her life, but she has yet to face the tension between her and Luann. They haven't spoken since the incident at Luann's cabaret five months ago.
A fractured group arrives at the Hamptons with Sonja straddling the line between the blondes and the brunettes. Luann, Bethenny, and friends head to dinner to discuss the night that forced Luann back into rehab. At a dueling dinner, Tinsley and Dorinda watch as Ramona fails to score with the local guys. When Barbara tries to bring the ladies together by throwing a clambake, things go from bad to worse.
Barbara's clambake continues as uninvited Ramona is confronted by Luann for spreading rumors, forcing her to leave with a doggie bag and without her pride. Back in the city, Dorinda and Barbara try to clear things up over lunch. Meanwhile, Bethenny heads to North Carolina for more relief work after the Hurricane Florence flooding. Sonja throws a party to celebrate a recent cover shoot for a fashion magazine where Dorinda and Luann finally come face to face.
Bethenny plays peacemaker between Dorinda and Luann. Later, Luann begins her court-ordered community service and discusses her first meeting with her parole officer. Tinsley tries to figure out what's going on with Scott and Ramona goes on a blind date.
Tinsley struts her way back into the charity world by hosting a doggy fashion show, followed by the ladies having brunch on board a yacht. It's all smooth sailing, except for Tinsley, who is interrogated about her future with Scott. Later, Bethenny speaks with a grief counselor about dealing with the loss of Dennis, and Dorinda readies Blue Stone Manor for the ladies' first Halloween there. At dinner in the Berkshires Luann throws a fit over room assignments.
Sonja is triggered when Dorinda organizes a trip to an old Morgan family mansion. Barbara is unhappy with her room allocation and the drama continues when Bethenny arrives from visiting her new beau. Over dinner, served by the Bear-Naked Chef, Sonja gets liquored up and starts spiraling down.
The Berkshires weekend winds down, but not before the ladies have one last wild night. Bethenny tells Dorinda about receiving a sign from Dennis, while Tinsley and Luann have heart to heart over the death of Tinsley's alcoholic father. When Bethenny hosts a dinner party in the city, a light-hearted game of truth or dare takes a dark turn for Tinsley.
Tinsley and Luann attend an Al-Anon meeting and Tinsley reveals news about Scott. Bethenny and Sonja head to an art gallery that is truly for the birds. Meanwhile, Dorinda joins Tinsley for a dress rehearsal before her big day as guest ringmaster at the Big Apple Circus. Ramona, Luann, and Sonja head to an Upper East Side haunt where they run into Ramona's ex, Mario. When Dorinda hosts a Spa Day for the ladies, conversations turn to makeups, breakups, lies, and apologies; making the day anything but relaxing.
Fresh off of her breakup with Scott, Tinsley and her mom, Dale, prepare for Tinsley's appearance as the guest ringmaster for the Big Apple Circus. Bethenny has a court appearance to confront the latest challenge in her custody battle with her ex. Meanwhile, Ramona takes Barbara shopping to help spruce up her wardrobe. At the circus, Tinsley's grand entrance, a descent from the rafters on a spinning hoop, foreshadows a descent into her true feelings regarding her breakup.
After learning that Bethenny missed her Halloween performance, Luann takes another dig at Queen B. Meanwhile, Dorinda shows off her new apartment to John, and says goodbye to her old apartment with Hannah. Proving no good deed goes unpunished, Ramona's attempt at charity devolves into chaos when she, Dorinda, and Sonja attempt to give a speech at the NY Loves Kids event.
Newly single Tinsley faces serious questions about having a baby. Sonja and Barbara head upstate to see Luann's new house, hoping to warn Lu of the rumblings among the other ladies about her behavior. Ramona, Bethenny, and Dorinda arrive, B confronts Luann, and shows Sonja and Barbara that their previous advice fell on deaf ears.
Bethenny continues to hammer into Luann about how narcissistic she's been. Ramona arrives, after her birthday celebrations, and the ladies dine out at the same place Ramona mourned her mother's passing. Luann takes Sonja, Tinsley, and Barbara out on the town for a night of cabaret, while Bethenny and Ramona have a heart to heart about their abusive upbringing.
After Sonja crashes Lu's rehearsal, Luann asks the women if they think Lady Morgan might be taking something to make her act this way. The ladies then head to Miami for fun, sun, and the revelation that Ramona made out with Harry Dubin. It's all too much for Sonja to handle, and after a few drinks she lashes out at Luann and Ramona.
On the first night in Miami, Sonja hits the floor after one too many drinks; the women turn their attention to Luann's attitude; the ladies rally to take in sunshine and art; at a house party, Ramona juggles her ex-husband, Mario, and a new date.
On day three of the Miami trip, Tinsley shows the ladies a recent picture online of Ramona locking lips with Harry Dubin. Barbara opens up about not feeling part of the group and the ladies confront her about making an effort. After leaving an AA meeting with Luann, Sonja loses it, but Luann doesn't let that rain on her cabaret parade. Over dinner the women confront Luann over her selfish ways, which turns into Bethenny having a full on panic attack.
The ladies head back to New York where Luann records her new single; the women attend Dorinda's 1980s aerobics workout for charity; Ramona plans a surprise birthday party on the same night as the Countess' Cabaret.
The show must go on for Luann, who performs in her Christmas Cabaret despite being snubbed by the ladies for Ramona's surprise party for Dorinda and Sonja. Dorinda is shocked by the party, but the real surprise is for Tinsley, who is accused of lying to the ladies about her relationship with Scott. Meanwhile, Bethenny recovers from a near death allergic reaction in time to throw her S'mores and Whores Party, filled with lots of surprises for everyone attending.
The ladies gather for Part One of the Season 11 Reunion where they discuss how Bethenny dealt with the death of her on-again, off-again boyfriend, Dennis. The women give updates on their new living situations, while Bethenny argues with Luann over whether paparazzi was actually following her. Dorinda and Luann finally address their friendship issues, starting with their unresolved issues from last year and what kept them at odds this year. Accusations are made, tears are shed, and Dorinda and Luann come to a conclusion about where they stand as friends.
In part two of the Season 11 Reunion, the women confront Ramona for her lies and insults. Dorinda, Bethenny, and Sonja challenge Tinsley to tell the truth about her relationship and living situation this season. Luann is put in the hot seat as Andy and the ladies discuss Luann's most recent sobriety slip and probation violation.
In the Season 11 reunion finale, the women finish raking Luann over the coals about her sobriety then look back on some of the highlights from their trips out of the city. Barbara joins the ladies to discuss her scandalous comment about Luann's singing and her ups and downs with the group. The ladies relive some of their most outrageous moments this season, and Sonja is in the spotlight for her drinking.