The ever-glamorous and self-indulgent Edina Monsoon (Jennifer Saunders) and her best friend Patsy Stone (Joanna Lumley) are now in their 60s. Edina is still trying to keep her PR agency afloat in London, but it is rapidly losing both money and interest. The dynamic duo quickly realizes that Edina requires a miracle to salvage her faltering business and restore her reputation.
The film begins with Bubble (Jane Horrocks), Edina's long-suffering personal assistant, waking up a hungover Edina, who has once again returned home intoxicated from a fashion event. It dawns on Edina that she has a meeting to sign a deal for an autobiography that very day. Eager to share the news, Edina wakes up Patsy and explains how her book, which narrates the story of her fabulous life, will be "made into a film." Meanwhile, Patsy self-indulgently applies Botox.
However, trouble arises when the head of the company (Mark Gatiss) dismisses Edina's book as poorly written and expresses that there is little interest in her PR agency. While Patsy sets up a fashion event for designer Huki Muki, she learns that supermodel Kate Moss is changing her PR representative. Patsy hastily informs Edina, who is currently at a PR meeting with rival Claudia Bing (Celia Imrie). During an attempt to call Edina, Patsy's phone inadvertently remains on speaker, revealing Kate Moss's need for a new PR to Claudia.
At the fashion event, Edina brings along her interracial teenage granddaughter, Jane "Lola" Johnson (Indeyarna Donaldson-Holness), unaware that her daughter Saffron "Saffy" Monsoon (Julia Sawalha) is also navigating her newly single life with a night out. As Edina spots Kate Moss on the balcony overlooking the Thames, she rushes to connect with the supermodel. In her haste, Edina collides with Kate, causing her to tumble into the Thames, sparking widespread panic and chaos.
As the media descends upon the scene to cover Kate's presumed death, Edina, Patsy, and Lola find themselves in police custody. The following day, an upset Edina returns home to find an angry Patsy, who has been dismissed from her job due to the previous night's drama. In a bid to make amends, the two return to the Thames to search for Kate, utilizing Bubble in their frantic efforts. Unfortunately, their misguided actions lead to Bubble's supposed demise, prompting the trio to consider fleeing the country to escape the growing media frenzy. They enlist Lola to finance their getaway.
Arriving in Cannes, France, Edina and Patsy seek help from Patsy's former lover Charlie (Barry Humphries), but he turns them down. Instead, they reach out to Edina's estranged elderly mother (June Whitfield), who is busy celebrating a family member's birthday. At this gathering, they encounter the Richest Woman in the World. To win her over for a quick financial fix, Patsy adopts a male persona, "Pat" Stone. Miraculously, Patsy ends up marrying the Rich Woman, which sets the duo on a path of wealth and luxury, sharing a posh hotel with the likes of Dame Joan Collins and Dame Edna Everage, who both appear as themselves.
Meanwhile, Saffy arrives in Cannes with her boyfriend Nick (Robert Webb) desperately searching for Lola. Saffy discovers that Lola is with Edina and is informed of Edina's location by Emma Bunton, who spots the duo out in public. The plot thickens as it’s revealed that Bubble has actually become a millionaire and owns a lovely pavilion in Cannes, having embezzled from Edina's accounts for years.
Frustrated by Edina's reckless behavior, Lulu (Lulu) reports Edina and Patsy's whereabouts to the police, leading to a frantic chase through Cannes. The pair tries to escape in a comically small fish-market van but find themselves in trouble when the brakes fail, and they roll into an infinity pool at Bubble's villa. Just then, Saffy arrives, witnessing her mother and Patsy precariously sinking in the van. Edina, feeling guilty for her choices, expresses a desire to no longer run from her age or consequences. Saffy reassures her of her love, while Bubble reveals that Kate is indeed alive and did not drown.
With this revelation, Edina gains newfound clarity and escapes the van as reports of celebrations break out across nations acknowledging Kate's survival and Edina’s reinstated PR agency. The film concludes with a joyous montage of Edina's revived career and Patsy's candid confession to her wealthy spouse that she is not actually a man as they revel in the upbeat tune "This Wheel's on Fire," performed by the fabulous Kylie Minogue.
