A young woman, Katherine, steps out for the morning newspaper and keeps walking. Wearing only her robe and slippers, she gets in her car and drives away, leaving behind her husband, Matthew, and their comfortable life in San Francisco. While Matthew tries to find her, Katherine hides away in a house on the water on Tomales Bay. Two drifters befriend her: Jake, who operates a herring boat on the bay, and Rich, a graduate school drop-out, his only crew. Jake and Rich develop a fascination for the mysterious Katherine, and their rivalry grows increasingly tense. Back home in San Francisco, Katherine's single friend, Claire, tries to console Matthew, and he reveals his deepest fear that Katherine has left him. When the tensions between Jake and Rich reach a breaking point, Rich's lies and Jake's ugly history come to the surface. A violent night reveals hard truths, long hidden, for all of them, including Katherine. In the light of day, Matthew heads north in a last effort to find his wife...