"Darling Companion" is the story of a woman who loves her dog more than her husband. And then her husband loses the dog.

On a wintry day, Beth (Keaton) saves a bedraggled lost dog from the side of the freeway. Struggling with her distracted, self-involved husband Joseph (Kline) and an empty nest at home, Beth forms a special bond with the rescued animal. When Joseph loses the dog after a wedding at their vacation home in the Rockies, the distraught Beth enlists the help of the few remaining guests and a mysterious young woman in a frantic search. Each member of the search party is affected by the adventure, which takes them in unexpected directions – comic, harrowing, and sometimes deeply emotional.