Saffron accepts a marriage proposal from Paolo, her pompous, controlling Italian boyfriend, to Edina's shock. Edina and Patsy travel to a ski resort in Val-d'Isère, France, but they are disappointed by the lack of celebrities in town. Later, a drunken altercation ensues when Edina points out their constant dependency on each other, destroying their chalet in the process. The next day, Edina loses control while skiing and nearly falls over a cliff. In a near-death experience, God (in the guise of Marianne Faithfull) appears to Edina in heaven, informing her that it is not her time yet. Back in London, Mother is brought home by a disguised Bo—who is hiding from Scientologists—after being mistaken for a terrorist at the airport, and realises she has forgotten to collect her American friends, Mac and Millie.

Edina and Patsy return home from Val-d'Isère. Upon discovering that Paolo's parents are wealthy and famous, Edina takes a sudden interest in Saffron's upcoming wedding. When Paolo's parents come to visit, his mother, Kalishia, disapproves of Saffron and refuses to allow Paolo to marry her. Patsy blackmails Kalishia into changing her mind by reminding her that they once co-starred in a Bond-inspired pornographic film. On the wedding day, Edina replaces Saffron's bridesmaid, Sarah, with Georgina, a Gucci model. When the vicar asks if there are any objections, Edina has another vision of God, who opposes the marriage. Edina interrupts the ceremony, prompting the guests to leave, while Paolo departs with Georgina. Though initially devastated, Saffron ultimately admits that Paolo was not right for her, before Edina and Patsy reveal that they are going on her honeymoon trip.

Edina and Patsy travel to Marrakech for a photo shoot. They are accompanied by Saffron, who is interested in studying the local indigenous peoples for school. There, Edina and Patsy meet up with an old friend, Humphrey, who sexually harasses Saffron. At dinner, it is revealed that in the 1970s, Patsy spent a year living as a man until "it fell off", according to Edina. The following day, during a shopping trip to an outdoor bazaar, a spiteful Patsy decides to sell Saffron to white slavers. Edina and Patsy later go to the photo shoot location, but when no one shows up, they end up lost in the desert. After wandering around for a day or two, the pair are rescued as they stumble upon Saffron, who is wearing a burqa. They spend the last few days of their trip drugged and unconscious, while it is implied that Saffron had a secret dalliance with Humphrey's houseboy.

Edina frantically organises her cluttered house in order to host old friends Bettina and Max, who were once obsessed with minimalism. Feeling ignored by Edina, Patsy leaves in search of another lunch partner. When Bettina and Max arrive, Edina is disappointed to learn that they are now the hysterical, neurotic parents of a newborn baby. As the couple wreak havoc, Edina quickly leaves the house. At a restaurant, Edina and Patsy compete against each other by attempting to befriend famous people: Patsy invites herself to lunch with Britt Ekland and Zandra Rhodes, while Edina forces her client Lulu to have lunch with her. Both lunches end awkwardly. Back home, while Saffron and Mother comfort Bettina, they hear Edina and Max having sex over the baby monitor. After the couple finally leave the intended result of Edina's fling she and Patsy make peace.

Edina begins an ad campaign for Prince Charles' biscuits, and claims that it is "by royal appointment". she begins to associate with the wealthy socialite crowd, and buys a weekend at a country house hotel. Upon arrival, Patsy and Edina discover that nothing is in season, and the place doesn't even have any jacuzzis or massage. Patsy tells Edina that the Rothschilds were laughing at her. Edina becomes angry and determines that she will kill something, and goes out with Patsy with guns blazing in the middle of the night. They bring a pheasant back to the hotel, which Edina puts in the closet. In the morning they discover that the pheasant is still alive. Patsy tells Edina to pull its neck but Edina bonds with it and drugs it and releases it into Hyde Park. At home, Emma and Sarah bring gifts to Saffron for a baby shower, and Sarah becomes obsessed with Emma. Sarah stalks Emma, and Saffron eventually calls the police and has Sarah arrested.

Edina discovers that both Marshall and Justin have cut off their alimony payments. After Saffron conspires with Edina's accountant, Edina is led to believe that she is poor, and reluctantly agrees to reduce her expenses. However, during a trip to the supermarket, she and Patsy fill three trolleys with groceries and steal a crate of champagne. Edina's "smaller" Alfa Romeo car is impounded outside Harvey Nichols, and the pair are later arrested for driving under the influence and several other charges, including assault and shoplifting. On the day of the trial, Edina goes on a rant in an effort to justify her actions, to no avail. In addition to a large fine, she and Patsy are sentenced to community service in a nursing home.

Unable to fit into the majority of her clothes, Edina becomes determined to lose weight. At the office, she is horrified upon learning of an upcoming visit by Penny Caspar-Morse, a thin model that used to torment Edina about her weight. Edina unsuccessfully attempts to exercise, and with Penny arriving earlier than expected, she accepts Patsy's suggestion to undergo a liposuction. After a disturbing nightmare about the procedure going horrifically wrong, Edina decides against the idea and instead puts on an oversized sweatshirt in order to cover herself up. Patsy announces that Penny is blind, much to Edina's delight. Later, Edina drunkenly rants at Penny about how she ruined her life and brags about how successful and thin she has become. However, she inadvertently reveals her weight as she grabs Penny's hands and places them on her waist.

As Edina and Patsy prepare to attend an underground rave on New Year's Eve, they receive an unexpected visit from Patsy's long-lost older sister Jackie. Patsy insists on taking Jackie along to the party, much to Edina's dismay. However, Patsy is disappointed to learn that Jackie is no longer the jet-setting, drug-addled party animal she used to be. Now homeless, Jackie asks Patsy if she could stay with Edina until she can raise money to open a shelter for stray cats and dogs. After helping Jackie loot Edina's bedroom for valuables she can sell to raise money, Patsy throws her out of the house, but it is too late to go the party a frustrated Edina has fallen asleep in the sitting room, surrounded by her family as the clock strikes midnight.

Edina & Patsy go on holiday in France, where they find themselves staying in a rustic cottage, instead of the château they were expecting. There is no food or wine, and the duo are constantly disturbed by an old Frenchman whose French they cannot understand. They are later rescued by Saffron, who arrives with supplies. Bubble comes along to deliver an urgent message concerning Edina's home decorating business, but she forgets about it. When Saffron reminds Bubble about the message, Edina panics and rushes to return home. The old Frenchman stops by again and repeats his message to Bubble, who understands perfectly that Edina and Patsy have been staying in the wrong place, and were expected in the château down the road. Later, customs detains the group when a suspicious white powder is found in Patsy's luggage, but they are freed when the powder turns out to be a harmless substance. Patsy, instead of being relieved, is horrified as she realises she actually enjoyed playing ping-pong.

Patsy helps Edina break in her new isolation tank upstairs, while Saffron works with classmates on a presentation for her sixth form college's open day. Edina is left feeling useless after Bubble, now a dedicated professional, takes charge of the office. She takes a sudden interest in Saffron's presentation and begs to be invited to the open day. When Saffron vehemently refuses, Edina throws a tantrum and threatens to adopt a Romanian orphan—to the point of instructing Bubble to send over a selection of babies so she can pick one. She then frantically tries to cancel the deal, but it is too late. Saffron eventually allows Edina to attend the open day. However, the presentation is interrupted as the babies arrive and start wailing, angering Saffron. Edina then wakes up in a panic, still in her isolation tank, and realises it was all a dream.

Edina is none too pleased about her 40th birthday. As opposed to the glamorous, star-studded surprise party she had hoped for, Edina is disappointed to learn that Saffron has planned a quiet lunch with family and friends—including both of Edina's ex-husbands, Justin and Marshall, and their respective new lovers, Oliver and Bo, as well as Patsy and Mother. Edina behaves erratically during the party, switching between self-pity and spite, and she soon provokes Oliver, her least favourite guest, into making an angry exit. Justin and Marshall are shocked to discover that they have both been paying alimony to Edina. While Edina and Patsy sing drunkenly on a new karaoke machine, Justin and Bo secretly plot to cut off Edina's alimony.

Edina is left feeling helpless after Saffron leaves home to attend university. Patsy loses her job when Ella magazine folds; she later receives an offer to work with her colleague Magda at a New York magazine. Edina and Patsy commiserate drunkenly with each other over old age and the sudden changes in their lives. Saffron returns for a visit, appalled at their behaviour. When Edina announces plans to sell the house before embarking on a journey of self-discovery, a livid Saffron storms off. Edina's plans also mean that she is cutting off Patsy. Embittered, Patsy leaves as she decides to take the job in New York.

Edina has a nightmare about Saffron's baby trying to stab her. It turns out that the face of the nightmare baby belongs to Saffron's midwife, who delights in teasing Edina about these nightmares. Edina expresses her displeasure about this baby. Saffron invites the father of the baby to the house to tell him she is pregnant. In the meantime, Edina and Patsy have organised a book club, but no one is interested in reading any books except celebrity magazines. When Edina discovers that John Johnson, the father of Saffron's baby is black, she is overjoyed, because she thinks a mixed-race baby is the greatest accessory, the "Chanel of babies." When Saffron tells John that she is pregnant, he replies that she should tell people that she is pregnant right away or people will think she is fat.

Edina builds a panic room. Patsy is at her shop, Jeremy's, when Minnie Driver walks in. Minnie complains about not scoring any free stuff from other shops at Bond Street, and takes pictures of herself shopping to sell to the paparazzi. Patsy is determined to become Minnie's stylist, so she later invites Minnie to Edina's house. She has gathered racks of designer outfits with which to dress Minnie. When Minnie wants a necklace that Edina is wearing, Patsy wrestles Edina for it, and they accidentally lock themselves in the panic room. They believe they will be unable to escape for days because Patsy panicked and kept pressing the buttons on the keypad. While they are locked in, they play Trivial Pursuit over the intercom and camera with Saffron. They also discover that Minnie Driver has taken all the designer clothes. At the end, Edina and Patsy discover they were locked in for only a couple of hours.

Saffron is preparing her home birth kit. She's due to have the baby anytime, Patsy is the hostess of the Style Awards at the Royal Albert Hall. Edina helps Patsy rehearse her speech but is interrupted by Katy Grin, Bo, and Marshall. Katy talks about her work in the musical Chicago. Bo and Marshall talk about their Christian Family Creation adoption service, which is a service for busy Hollywood actresses who have no time or desire for pregnancy. Saffron and Patsy shove each other trying to get up the stairs, and then suddenly Saffron's waters break, spilling baby juice all over Patsy's expensive clothing. Saffron retreats to her bedroom with contractions. In a rare moment of support for her daughter, Edina tells Patsy she won't be able to go to the awards show. Saffron eventually gives birth to a healthy baby girl.

After awakening with a hangover, Edina 'Eddie' Monsoon frantically prepares to launch a major fashion show. Meanwhile, her unsympathetic daughter, Saffron—whom Edina had promised to quit drinking—constantly reprehends her mother's unhealthy habits. Edina's best friend, Patricia 'Patsy' Stone, arrives to accompany her to work. At the office, Edina's assistant Bubble reports that one of the main models, Yasmin Le Bon, has dropped out, while Princess Anne has replaced Princess Diana on the guest list. Edina subsequently manages to cajole several B-list celebrities into attendance, turning the show into a rousing success. Later that night, Edina and Patsy indulge in a drunken bender—much to the disgust of Saffron, who locks Edina out of the house. The next morning, Edina and Patsy trick Saffron into believing that Edina is going to check into a rehabilitation clinic.

Saffron grows impatient with Edina's unwillingness to have their kitchen remodelled after Patsy accidentally burnt it down. Edina's obsession with finding a particular door handle for the kitchen leads her and Patsy to New York City. After a shopping spree, Patsy persuades Edina to have her navel pierced. Edina finally finds and photographs the door handle at the Four Seasons Hotel. Upon returning home, Edina not only fails to notice that Saffron has had the kitchen refurbished in her absence, but learns that she has forgotten her daughter's birthday.

Edina's home is a mess, and she has done some more remodelling as usual. The changes include a pool in her bathroom, and a shower that washes and buffs her like a car wash. Her new client Emma Bunton comes by to discuss new jobs. It turns out Saffron was Emma's head girl at school and Emma knows that Saffron would be disturbed by Edina's squalid house. When they realise that Saffron is coming home that day from volunteer work in Africa, Emma urges everyone to clean up. Patsy gets obsessed by organising a drawer full of odds and ends. When Saffron arrives, Edina taunts Saffron for becoming fat and fulfilling her "genetic fate." Saffron informs her that she is not fat, she is pregnant. Edina tells Saffron that she should tell people that she is pregnant right away or people will think she is fat.

Edina's 'new' boyfriend Pete is a tape engineer who used to work at Abbey Road Studios during the time that the Beatles recorded there, and who had found some unreleased tapes. In a studio, the girls have fun and Edina sings her 'walking down the road' song she loves. There are flashbacks from the sixties where Patsy is a man and they are at a recording for the Sgt. Pepper album. Back at home, Elton John had been invited to the party to debut the Beatles tapes, but gets annoyed and leaves when he discovers he was only invited to play piano in the background. Finally, just after proposing marriage to Edina, Pete plays the tapes at the party. Instead of The Beatles, Edina is heard singing. Apparently this is because Patsy had pressed the record button on the recorder in the studio by mistake whilst she was looking for champagne in the control room, and Edina unknowingly sang over the tapes.

Edina decides to remodel the kitchen again, and calls up her old minimalist friends. It turns out Bettina is divorced and is clinically insane and Max is revealed to be gay. Bettina transforms the kitchen into a stairless white box, but Edina hates it. Patsy, meanwhile, develops serious health problems and walks around with an IV stand. Saffron returns from her wedding to John in Kenya and reveals that he is a polygamist. Edina and Patsy head off to meet designers Terence Conran and Kunz for inspiration. At Kunz's store, Edina claims to have seen her ideal kitchen in a previous life, so she hires a channeller. The channelling session results in so much disruption in the household that Saffron and Edina argue once again, and Edina lashes out at baby Jane in anger. Saffron has finally reached breaking point, and kicks Edina and Patsy out of the house, which is in her name. Edina and Patsy end up lounging in the stylish window display of Terence Conran's Shop.

Patsy becomes the subject of a tabloid sex scandal following an affair with a married MP. Edina checks into a hospital for surgery after injuring her big toe. Patsy tags along, planning to undergo a chemical peel in preparation for her interview with Hello! magazine. While anesthetised, Edina dreams that she is on her deathbed, surrounded by idealised versions of family and friends, while Patsy envisions herself looking young for her Hello! spread. Edina awakens to find that her pains were caused by a stray acupuncture needle that worked its way from her cranium to her toe. Meanwhile, a botched facelift leaves Patsy's face covered in burns. The Hello! spread is also a disaster, with the article reporting Patsy's age as 49, blaming her for the sex scandal and revealing her horrific facelift.

Patsy accidentally burns down the Monsoons' kitchen with a cigarette. She and Edina later plan a night out, but they decide to stick around after learning that Saffron is expecting a date, much to her chagrin. To make matters worse, Mother inadvertently locks the three women in the living room on her way to the chemist's. Edina pesters a mortified Saffron with questions about her sex life, before the trio exchange stories about their own births. Patsy—who had a neglectful mother—expresses her resentment towards Saffron due to the privileges she enjoyed while growing up, leading to a bitter dispute between the two. When Mother eventually returns home and unlocks the door, Edina and Patsy quickly leave, while Saffron's date is waiting outside. A flashback sequence shows Edina as she plans to surrender Saffron for adoption.

Edina becomes frustrated when she loses a prestigious PR award to rival Claudia Bing, despite having bribed the judges. Worried about her dwindling career, Edina works on a campaign in hopes of upstaging Claudia. Meanwhile, Saffron becomes romantically involved with Gerard, her psychology lecturer, until she discovers that he is married with children. In a rare occurrence, Edina comes to Saffron's aid by punching Gerard in the face. At an industry luncheon, Edina's speech is stolen, prompting a drunken rant against the bastardisation of the PR industry, which proves a success. When Edina and Patsy attempt to retrieve the speech, the duo awaken the next morning on a trash barge headed for Ostend.

Patsy has booked Saffron's baby Jane (Lola) for a photo shoot with Jean-Paul Gaultier. Gran usually babysits Jane on Thursdays, so that Saffron can go out with John. But Gran does not come this Thursday, because Edina has banned her from the house. So Saffron and John are stuck at home, and Patsy can not take the baby to the photo shoot. Patsy and Edina prey on Saffron's insecurities and tell her that John will lose interest in her, Saffron bursts into tears and agrees and asks Edina to look after Jane while she goes out with John. Edina and Patsy plan to take the baby to have a photo shoot at the London Zoo. Saffron returns and finds out they took the baby out against her wishes and Edina explains that she has bonded with Jane, however it is later discovered that Edina has brought home the wrong baby.

Edina enrolls in a boot-camp fitness programme and subjects herself to a strict diet, after being ridiculed for her weight by Katy Grin, Catriona and Fleur. Meanwhile, Patsy briefly experiments with pulling back her signature fringe for the first time in decades, and budding playwright Saffron receives a visit from Taylor, a pretentious old school friend with acting aspirations. Despite initially struggling, Edina's efforts soon pay off as she realises she has lost one stone. Proudly displaying her slimmer figure, Edina meets her friends again for lunch, but her weight loss is still not enough to deter Katy Grin's snide remarks.