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

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

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

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

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

Patsy, who is temporarily staying with the Monsoons, becomes jealous when Edina reconnects with an old boyfriend. During one of her sporadic appearances at work, Patsy is assigned to host a fashion makeover segment on a morning television show. After clashing with the models, Patsy attempts to persuade Saffron and Mother to appear on the show in their place, telling a tale of her emotionally distant mother