When Fiona Gordon was just a child, her aunt Martha moved from a quaint village in Canada to the vibrant city of Paris. Fast forward to years later, Fiona receives an urgent letter from her aunt, requesting her presence in Paris as she faces the imminent threat of being placed in an assisted living facility at the age of 88.
Upon her arrival in the City of Lights, Fiona is met with an unexpected twist: her aunt is nowhere to be found. In a comical mishap while posing for a photo near the iconic Eiffel Tower, Fiona tumbles into the Seine, losing her backpack in the process. This fateful bag is discovered by Dom Abel, a quirky man who resides in a tent by the riverside. In a rather opportunistic move, he uses Fiona's money to indulge himself in a sumptuous meal at a fancy restaurant, where their paths cross once more. As they dance and Dom offers his assistance to walk her home, a sense of camaraderie begins to bloom. However, Fiona’s unease grows when she spots her own purse in Dom's possession, leading to a confrontation that sends her back into the Seine for a second time.
Amidst the chaos, Dom discovers his feelings for Fiona and takes it upon himself to return her backpack to the Canadian embassy, allowing her to retrieve it. Determined, Fiona embarks on a quest to locate her aunt, only to receive the shock of her life—she learns Martha has passed away, with the funeral taking place that very day. Accompanied by Dom, she attends the service, where he unexpectedly offers a eulogy. Despite not knowing Martha, he makes an enthusiastic speech, revealing her secretive flaws, claiming she was a closet racist who had disdain for poorly dressed individuals and the homeless alike.
It dawns on Fiona during the reception that she is actually mourning Marthe, a friend of her aunt's. In a hilarious turn of events, as Fiona examines the coffin, Dom finds himself in a comedic bind with the coffin lid closing on his tie, leading to an absurd situation where Fiona's nose gets trapped in an elevator while trying to help him. Upon regaining consciousness, she holds an urn expecting it to be filled with both Marthe’s and Dom’s ashes, only to find that Dom is very much alive, resulting in a furious slap from Fiona.
Meanwhile, during this time, Martha has been evading the persistent nurses from the retirement home, seeking refuge from their advances. In a twist of fate, she coincidentally encounters Dom, who is also reeling from his encounter with Fiona. That night, after Fiona drifts into sleep at Martha's flat, both she and Dom have erotic dreams featuring one another, culminating in Dom's escapade with Martha. The next morning, Martha scavenges through a trash bin and retrieves Fiona's phone, leading to a bewildering conversation where hints about her rendezvous in New York surface. Fiona makes the crucial deduction that Martha is cozying up near the replica of the Statue of Liberty on Île aux Cygnes. Eager to reunite, she seeks Dom’s help to track down her aunt.
Utilizing his dog to sniff out clues, they venture out to locate Martha. Climbing up the majestic Eiffel Tower, they finally find Martha nestled in a satellite dish, peacefully asleep. Pausing to savor the breathtaking panorama of the city, the trio's moment is bittersweet as they come to grips with fate when Martha quietly passes away.
Following her cremation, a poignant farewell takes place at Île aux Cygnes, where Fiona and Dom release her ashes into the Seine. In a moment of reflection, Fiona expresses her long-held desire to learn French, prompting Dom's heartfelt agreement to guide her on this new journey.