Miriam and Claudette Colbert and her ex-husband, Macdonald Carey, are nearing the conclusion of their divorce, which Miriam initiated due to Hugh's persistent gambling habits. Their adult daughter, Barbara, lives with Miriam in the family home, along with Barbara's husband, Jerry Denham, played by Robert Wagner, and their young daughter, Annabelle. Hugh, meanwhile, resides at the Hotel Miramar in Santa Monica, where he is the head of publicity. Jerry hopes to move out, aiming to give Barbara more independence, but Barbara insists she prefers to stay, wanting to keep Miriam company and avoid leaving her alone.
The story unfolds with the introduction of Victor Macfarland, a wealthy and influential financier who is rumored to be considered for the next appointment as the American representative to the International Monetary Fund (IMF). During his rare visit home, he stays at the Miramar, which sets the stage for tension. Hugh, who was once a rival to Victor back in high school for Miriam's affections, shows clear displeasure upon seeing him again. Miriam, for her part, is distant from Victor, having not heard from him since he abruptly left town 20 years earlier.
Hugh's ongoing care for his prized rose bushes leads to several scenes where he spends time at their house, much to Miriam's annoyance. On the last day before their divorce is finalized, Hugh promises to quit gambling, and Miriam agrees to dine out with him. However, Hugh's resolve falters when his bookie calls to inform him of a recent winning bet. Just at that moment, Victor arrives, and Miriam, irritated by Hugh’s persistence, invites Victor to stay for dinner. Meanwhile, Hugh seethes alone on the patio. Inside, Miriam and Victor share a dance, culminating in a champagne toast at midnight celebrating the official end of their marriage.
Their interactions at the Miramar grow more intertwined, as Victor and Miriam's relationship blossoms under the eyes of the community. Hugh tries to undermine them by introducing Victor to Joyce Mannering, Marilyn Monroe, a charming beauty contest winner and model, though Victor seems indifferent to her. Despite her initial resistance, Miriam eventually agrees to travel with Victor, but she reminds him of her responsibilities as a mother and grandmother, hinting at her hesitations about pursuing the relationship further. Victor, however, is persistent; he prevents her from leaving his hotel room, and she returns home with a lavish engagement ring, announcing her plans to marry Victor in just three days.
The day before the wedding, Victor confesses to Barbara that he must leave for Washington, D.C., that evening to attend a hearing regarding his IMF appointment. He persuades Barbara to follow him the next day so they can marry before he leaves. Before departing, Miriam confronts Victor about his sudden abandonment 20 years prior. In a moment of honesty, he admits that he and Hugh had played craps for her, and he lost, revealing the reason for his silence all these years.
Furious and heartbroken, Miriam calls Hugh to express her anger. She threatens to destroy his rose bushes, and, intoxicated, Hugh visits the house after dark to transplant them himself. He enlists Jerry's help, but their actions result in their arrest by passing police officers. Jerry calls Miriam to identify Hugh and himself at the station, and the next morning, the media pick up the story, with photographs of Miriam leaving the police station with Hugh, now an ex-husband.
The scandal complicates Victor’s plans, leading him to advise Miriam to stay away from the public eye until his confirmation. Their heated phone conversation ends with Miriam calling off the engagement. When Hugh later comes to pick up his remaining belongings, Miriam confesses that she cannot forgive him for gambling over her, feeling it proved he never truly loved her. Hugh, revealing he always carries the dice he used, asks Miriam to roll them. She does, and they always come up three and four. Hugh admits he cheated, risking everything. Understanding and remorseful, they share a heartfelt kiss, bringing their story to a close, marked by a blend of forgiveness and acceptance amid complex relationships.
