Anne, portrayed by Olivia Colman, pays a visit to her father, Anthony (played by Anthony Hopkins), who has been acting aggressively towards his new caretaker. Struggling with dementia, Anthony frequently forgets significant life events and misplaces his belongings around his home, including his watch, which he insists has been stolen. In a moment of confusion, he confronts Anne about his supposed stolen watch and expresses his determination to never leave his flat.
Complicating matters, Anne reveals her plans to relocate to Paris with her new boyfriend, causing Anthony to question this since he mistakenly believes she is still married to James. Anne gently reminds him they divorced five years earlier, and in a sorrowful farewell, she departs.
The following day, Anthony encounters a stranger, Paul, played by Mark Gatiss, who insists that Anthony lives with him and Anne. When Anne returns from shopping with dinner, she appears to have transformed into a different woman, embodied by Olivia Williams. This perplexes Anthony, prompting deep frustration about his surroundings.
Anne arranges for a new caretaker, Laura (played by Imogen Poots), to interview at his home. Despite insisting he needs no assistance, Anthony awkwardly claims he used to be a professional dancer and that Laura reminds him of his estranged daughter, Lucy, whom he hasn’t spoken to in months for reasons that elude him.
During a visit to a doctor, Anthony confidently declares that he does not have memory problems, insisting he is fine. He takes pride in Lucy—as a painter—but is oblivious when Laura expresses her condolences regarding her tragic accident, which he cannot recall. As the narrative unfolds, it becomes evident that Anthony has been under the impression he lives in his own flat, but in reality, he has been residing with Anne and Paul for years.
The tension escalates when Anne and Paul have a disagreement sparked by the strain of managing Anthony's increasingly belligerent behavior. Paul again confronts Anthony, pushing him to the brink of tears through emotional conflict.
In a sudden shift, Anthony finds himself disoriented in a hospital corridor, plagued by memories of Lucy’s devastating car accident. Disturbingly, he recalls the sight of her bloodied body, only to awaken in a nursing home, where he is cared for by Catherine (Olivia Williams) and Bill (Mark Gatiss). In this new reality, Catherine reveals that Anne has moved to Paris with Paul and now visits only on weekends.
Overwhelmed and unable to grasp his changing world and Anne's absence, Anthony breaks down emotionally, longing for his mother and lamenting that he feels like he is "losing his leaves." In a moment of tenderness, Catherine reassures him, promising an outing to the park later that day.
The film poignantly closes with a serene shot of leaves rustling gently on a tree, encapsulating the tragic beauty of Anthony's journey through dementia.
